Saturday, December 3rd, 2016. A 307-digit cofactor of 149¹²⁰ + 120¹⁴⁹ was cracked by SNFS. Sieving was done by Ryan Propper just in a week, linear algebra was completed by Greg Childers in another three weeks. Awesome scale.

Saturday, November 26th, 2016. The largest prime factor record was broken by NFS@home. They found a 133-digit factor of a 272-digit composite, completing the factorization of 136¹⁰⁵ + 105¹³⁶.

Saturday, October 8th, 2016. Ryan Propper revenged with 300 digits. That SNFS record completed the factorization of 141¹³³ + 133¹⁴¹. Again, a septic polynomial was used here.

Friday, September 30th, 2016. The total number of the composites was reduced to 700.

Monday, September 12th, 2016. No composites left with less than 180 digits.

Thursday, September 1st, 2016. All the composites passed ECM tests with B1 = 43M. Thanks to yoyo@home!

Wednesday, August 31st, 2016. Once again NFS@home raised its own GNFS record, this time to 197-digit mark.

Sunday, August 28th, 2016. A 286-digit divisor of 139¹²² + 122¹³⁹ was factored by NFS@home project, taking back the SNFS record.

Friday, July 15th, 2016. Ryan Propper raised his SNFS record to 282-digit mark! He used a septic polynomial to complete the factorization of 140¹³⁷ + 137¹⁴⁰.

Wednesday, July 13th, 2016. A new GNFS record came from NFS@home project, now at 188 decimal digits.

Sunday, July 10th, 2016. The total number of the composites was reduced to 800.

Monday, July 4th, 2016. Ryan Propper factored a slightly larger 267-digit composite with SNFS, completing the factorization of 150¹¹⁸ + 118¹⁵⁰.

Friday, May 13th, 2016. All the numbers up to x = 120 inclusively had been completely factored.

Sunday, May 8th, 2016. The factorization of the second largest XYYXF number, 150¹⁴⁸ + 148¹⁵⁰, was finished with SNFS by NFS@home project. Although the cofactor had only 200 digits, the corresponding SNFS difficulty was 285, so the whole job took more than three months.

Friday, April 22th, 2016. All the numbers with y < 41 had been completely factored.

Tuesday, April 19th, 2016. The total number of the composites was reduced to 900.

Thursday, April 14th, 2016. Tom Womack completed the factorization of 144¹⁴² + 142¹⁴⁴, establishing a new SNFS record at 267 digits and proving that a single person still can beat the powers of grid computing.

Tuesday, January 19th, 2016. This time NFS@home project raised its own GNFS record to 185-digit mark.

Tuesday, September 8th, 2015. A third record at a run, eventually for the largest prime factor, was established by NFS@home project. They found a 123-digit prime factor of a 257-digit composite, completing the factorization of 135⁸² + 82¹³⁵.

Thursday, September 3rd, 2015. The SNFS factorization of a 262-digit composite was completed by NFS@home project, beating the previous record by 8 digits and completing the factorization of 132¹⁰¹ + 101¹³².

Sunday, August 23rd, 2015. A new GNFS record, of 182 digits, came from NFS@home grid.

Monday, August 10th, 2015. No composites left with less than 170 digits.

Friday, July 31st, 2015. The total number of the composites was reduced to 1000. A real milestone there!

Friday, June 19th, 2015. A 179-digit composite was factored with GNFS by NFS@home. That's a record again!

Saturday, May 23rd, 2015. Ryan Propper took a revenge cracking a 254-digit cofactor of 127¹⁰² + 102¹²⁷ with SNFS just in two weeks.

Wednesday, May 20th, 2015. Another GNFS improvement by NFS@home: 174 digits this time.

Sunday, May 10th, 2015. A slightly larger GNFS record, at the same 170 digits, was established by NFS@home.

Monday, April 27th, 2015. Ryan Propper again improved his own record with a 116-digit prime factor of 128⁸⁹ + 89¹²⁸.

Sunday, April 5th, 2015. The NFS@home grid raised its SNFS record to 253-digit mark, completing the factorization of 137⁸⁰ + 80¹³⁷. At the same time Ryan Propper completed a 251-digit task that would have become a record if NFS@home had been a bit late. Luckily, Ryan's efforts on 126¹⁰³ + 103¹²⁶ yielded a 108-digit prime factor and set a record anyway.

Thursday, March 26th, 2015. A 64-digit factor of 138⁵⁹ + 59¹³⁸ was found with ECM by Ryan Propper. The factor of record size appeared in step 1 of ECM procedure!

Monday, March 9th, 2015. All the numbers up to x = 115 inclusively had been completely factored.

Monday, February 9th, 2015. Ryan Propper found a 107-digit prime factor of 115⁹⁷ + 97¹¹⁵, setting up a new record. That's the first 100+ digit factor ever found here.

Tuesday, February 3rd, 2015. A new GNFS record, of 170 digits, was established by the NFS@home factoring grid.

Monday, February 2nd, 2015. The XYYXF site changed its location from http://xyyxf.at.tut.by/ to http://www.primefan.ru/xyyxf/default.html.

Thursday, January 22nd, 2015. The total number of the composites was reduced to 1100.

Sunday, August 3rd, 2014. Mark Rodenkirch found that four PRPs, 4076¹⁴⁶⁷ + 1467⁴⁰⁷⁶, 11473³⁸³⁴ + 3834¹¹⁴⁷³, 11487¹⁴⁹⁰ + 1490¹¹⁴⁸⁷ and 11736²⁸⁶⁹ + 2869¹¹⁷³⁶, were missing from the Primes page. His massive double-checking efforts spread up to x = 12500. Great thanks to Mark!

Sunday, July 13th, 2014. The NFS@home grid factored a 169-digit composite, establishing a new GNFS record.

Thurday, May 15th, 2014. Serge Batalov found a probable prime of record size. That's 328574¹⁵ + 15³²⁸⁵⁷⁴ with 386434 decimal digits. Congratulations!

Monday, May 12th, 2014. A subforum for the project was created at mersenneforum.org. Welcome!

Wednesday, February 5th, 2014. MSieve 1.52 was released.

Sunday, December 15th, 2013. The total number of the composites was reduced to 1200.

Friday, November 15th, 2013. And again GNFS record, with the same decimal length of 168-digits by the same contributor NFS@home.

Monday, November 11th, 2013. The 168-digit cofactor of 127¹¹⁰ + 110¹²⁷ became a new GNFS record. Greetings to NFS@home project!

Monday, September 9th, 2013. The NFS@home grid completed the factorization of 129⁸² + 82¹²⁹, raising its own SNFS record to 244 digits.

Saturday, August 10th, 2013. A new GNFS record of 164 digits was set by Sean Wellman. The whole job took less than a month, while the polynomial search took just 2 days on a single machine.

Friday, May 31st, 2013. All the numbers up to x = 110 inclusively had been completely factored.

Sunday, February 17th, 2013.MSieve 1.51 was released.

Saturday, December 29th, 2012. Our newcomer, NFS@home, debuted with a new SNFS record at 242 digits completing the factorization of 119¹⁰⁹ + 109¹¹⁹. A good start, really :-)

Tuesday, December 11th, 2012. 8656²⁹²⁹ + 2929⁸⁶⁵⁶, a number with 30008 decimal digits, was proven prime by Jens Franke et.al. with a new algorithm called CIDE breaking the world record in general purpose primality proofs. Two more probable primes were reserved, with more than 50k and more than 100k decimal digits respectively.

Monday, November 12th, 2012. No composites left with less than 154 digits. Thanks to Sean Wellman and his GNFS efforts.

Tuesday, June 26th, 2012. The total number of the composites was reduced to 1300.

Saturday, May 12th, 2012. The concept of "wanted composites" vanished.

Wednesday, April 25th, 2012. Sean A. Irvine found a 99-digit prime factor of 130⁶⁴ + 64¹³⁰, setting up a new record. It took just 10 days to make the factorization, but more than three years to beat the previous record.

Friday, February 3rd, 2012. MSieve 1.50 was released.

Sunday, July 24th, 2011. The total number of the composites was reduced to 1400.

Monday, May 30th, 2011. All the composites passed ECM tests with B1 = 11M.

Monday, May 2nd, 2011. The ECM server retired from the work after nine years of activity. Great thanks to Greg Childers who maintained the server for such a long time.

Thursday, March 31st, 2011. The total number of the composites was reduced to 1500.

Friday, February 18th, 2011. A probable prime with more that 300k digits, 314738⁹ + 9³¹⁴⁷³⁸, is found by Anatoly Selevich. Congratulations to him!

Saturday, November 13th, 2010. The total number of the composites was reduced to 1600.

Sunday, September 19th, 2010. MSieve 1.47 was released.

Wednesday, June 30th, 2010. All the numbers up to x = 105 inclusively had been completely factored.

Wednesday, June 9th, 2010. Göran Hemdal reported that three PRPs, 3782³¹⁵ + 315³⁷⁸², 3784³¹⁵ + 315³⁷⁸⁴ and 3789²⁹³² + 2932³⁷⁸⁹, were missing from the Primes page. Thanks to Göran for double-checking the computations!

Tuesday, June 8th, 2010. This time RSALS beat an SNFS record completing the factorization of the 242-digit factor of 125⁸⁶ + 86¹²⁵. Just have no words.

Thursday, April 22nd, 2010. A 62-digit factor of 134⁷⁸ + 78¹³⁴ was found with ECM by yoyo@home. An impressive record.

Sunday, April 11th, 2010. The total number of the composites was reduced to 1700.

Saturday, April 3rd, 2010. So far, GNFS reached 163 digits. It was, as usual, RSALS sieving grid supported by Lionel Debroux and Jeff Gilchrist. Already five GNFS records in less than four months...

Friday, February 26th, 2010. And yet another GNFS record, again by RSALS, two digits longer.

Friday, February 19th, 2010. RSALS sieving grid raised the GNFS record to 158 decimal digits. A true power.

Wednesday, January 13th, 2010. A new ECM record of 57 digits was reported by yoyo@home. This powerful BOINC grid made a lot of ECM work for our project. Congrats to yoyo!

Monday, December 7th, 2009. Two new GNFS records, at 150 and at 151 decimal digits, were established by the powerful RSALS sieving grid with a help of Lionel Debroux and Jeff Gilchrist. Both huge tasks took only 8 calendar days to complete. Congratuations to the RSALS team!

Wednesday, November 25th, 2009. The total number of the composites was reduced to 1800. Quite a speed.

Thursday, November 19th, 2009. No prime factors of 122⁹³ + 93¹²² were known until Greg Childers factored this really huge number with SNFS, setting up an SNFS record at 241 digits which is quite hard to beat. This just reminded me a seven years older 188-digit SNFS record by Paul Leyland. At that time, in 2002, it was unbelievable that a 195-digit SNFS job would not fit the Top-20. But with Greg's new result the last C195 fell out of the table.

Grand respects and congratulations to Greg Childers, the man with the largest contribution to our project.

Thursday, August 20th, 2009. The total number of the composites was reduced to 1900.

Monday, July 20th, 2009. MSieve 1.42 was released.

Tuesday, June 23rd, 2009. The list of the wanted composites was significantly expanded due to Greg Childers' SNFS efforts. :-) About 170 new numbers were added, preferably with smaller x's and SNFS difficulty < 200.

Thursday, May 21st, 2009. Sean A. Irvine set up a new GNFS record of 147 digits. It took 17 days to complete the factorization of 118⁸² + 82¹¹⁸.

Monday, April 27th, 2009. The total number of the composites was reduced to 2000. That's an ECM attack!

Monday, February 16th, 2009. Jeff Gilchrist published a nice Beginners Guide to NFS factoring using GGNFS and Msieve to help newcomers with applying GNFS and SNFS tools.

Wednesday, February 11th, 2009. Greg Childers made a nice SNFS-split of 143²⁵ + 25¹⁴³, yielding a record-size prime factor of 98 digits. Quite close to the googol barrier!

Tuesday, January 27th, 2009. The total number of the composites was reduced to 2100. The 2k milestone is definitely reachable within 2009.

Monday, January 5th, 2009. Serge Batalov factored 124⁶⁵ + 65¹²⁴ just in 10 days, setting up two XYYXF records, for the largest prime factor (96 digits) and for the largest factorization (225 digits). By the way, no prime factors of this number were previously known. Congratulations again Serge!

Tuesday, December 2nd, 2008. MSieve 1.39 was released. A lot of changes, tweaks and fixes.

Thursday, September 25th, 2008. MSieve 1.38 was released. Square root became twice faster, a lot of other enhancements.

Friday, June 6th, 2008. A new page, Primes and PRPs of the form x^y + y^x, appeared on our site. These tables were originally maintained by Paul Leyland, but became outdated with time, so there's a new version, somehow revised and supplemented with the latest results.

Thursday, May 29th, 2008. Our newcomer, Serge Batalov, raised the ECM record up to 56 digits, completing the factorization of 114¹⁰³ + 103¹¹⁴. Congratulations Serge!

Saturday, May 17th, 2008. MSieve 1.36 was released. Just awesome.

Thursday, May 1st, 2008. The total number of the composites was reduced to 2200. We're getting quicker :-)

Thursday, February 14th, 2008. Hallstein A. Hansen and Lars Solem raised the SNFS record up to 215 digits, completing the factorization of 131⁴⁴ + 44¹³¹. The job was done in less than 3 months.

Tuesday, December 18th, 2007. A bit higher GNFS record this time: the 144-digit cofactor of 141⁹⁷ + 97¹⁴¹ was cracked just in 12 days by Sean A. Irvine.

Friday, November 16th, 2007. MSieve 1.30 was released. The best NFS-postprocessing tool in the world.

Sunday, October 28th, 2007. All the numbers up to x = 100 inclusively had been completely factored. It's a real milestone! Almost 6 years had been passed since there numbers were involved in the project. Greetings go out to our contributors, and especially to Greg Childers and Sean A. Irvine who worked purposely on the x < 101 numbers all this time. Well done people!

Thursday, October 18th, 2007. The total number of the composites was reduced to 2300. A good rate!

Sunday, September 9th, 2007. Hallstein A. Hansen improved his own GNFS record to 142 digits, completing the factorization of 150⁴⁸ + 48¹⁵⁰.

Wednesday, September 5th, 2007. All the numbers up to x = 95 inclusively had been completely factored.

Wednesday, August 29th, 2007. All the numbers up to x = 100 were included in the wanted list.

Saturday, July 28th, 2007. Hallstein A. Hansen cracked a larger C139 with GNFS and hit the 1st place.

Wednesday, May 2nd, 2007. MSieve 1.20 was released. Awesome work Jason.

Monday, March 12th, 2007. Hallstein A. Hansen established an overwhelming QS record of 126 digits. He completed the factorization of 148³² + 32¹⁴⁸ in six months using MSieve 1.12. What a patience!

Friday, January 12th, 2007. MSieve 1.15 was released. Still slow, but already working NFS implementation.

Saturday, October 28th, 2006. A new record-breaking factorizaiton: Tony Galvan found a 55-digit prime factor of 103⁹² + 92¹⁰³ with ECM.

Sunday, September 10th, 2006. The total number of the composites was reduced to 2400. You see, the speed of the factoring process became as low as exactly one hundred per year. The next hundred of composites will probably take several years...

Friday, August 25th, 2006. MSieve 1.10 was released. A few more updates and we'll have a tiny and powerful factoring utility.

Wednesday, June 7th, 2006. Another GNFS record, one digit larger and 3 days longer. Congrats to Sean A. Irvine for completing the factorization of 95⁸⁴ + 84⁹⁵!

Saturday, April 22nd, 2006. MSieve 1.06 was released. A few QS improvements, and the dawn of NFS support. Well done Jason!

Thursday, February 2nd, 2006. Sean A. Irvine set up a new amazing record for GNFS. It took 8 days to split a 138-digit cofactor of 95⁸⁹ + 89⁹⁵.

Sunday, November 27th, 2005. MSieve 1.03 was released. This version appeared to be about twice faster.

Wednesday, November 2nd, 2005. Three lost factorizations were restored. All of them were made by Larry Soule more than 3 months before but unfortunately I missed them at the time.

Saturday, September 10th, 2005. The number of the composites was reduced to 2500.

Sunday, July 24th, 2005. A new table appeared on the Records page. It collects 20 largest prime factors ever found in the project.

Friday, July 22nd, 2005. MSieve 1.01 was released.

Sunday, July 3rd, 2005. Don Leclair, Sean A. Irvine and Jes Hansen improved recent SNFS record to 205 digits. The job took 25 days, and the pretty result is C205_116_65 = P86*P119.

Tuesday, June 28th, 2005. Tom Cage factored a 117-digit composite factor of 146⁷² + 72¹⁴⁶ with SIQS in 13 days, making an impressive 3-digit improvement to the old record.

Saturday, June 18th, 2005. MSieve 1.0 was released.

Wednesday, June 8th, 2005. Another GNFS improvement from Sean A. Irvine: the 132-digit composite cofactor of 94⁸⁹ + 89⁹⁴ took just six days to be cracked. Magnificent.

Wednesday, June 1st, 2005. Please upgrade your ECM client to version 2.6.1.

Friday, May 27th, 2005. The largest number with x under 101, namely 100⁹⁹ + 99¹⁰⁰, was factored using SNFS by Jes Hansen, Samuel Chong and Dennis Klemann. With SNFS difficulty of 202 digits (comparable with current SNFS record) this task took more than a month of collaborative work. Well done people!

Wednesday, April 27th, 2005. All the numbers with y < 16 had been completely factored.

Sunday, March 27th, 2005. Don Leclair factored a 200-digit composite number with SNFS. It was a cofactor of 103⁸⁹ + 89¹⁰³. This awesome job took 35 days: twenty days of sieving, two weeks of linear algebra, a few hours of square root phase. And the factors are excellent: C200_103_89 = P95*P105. Congratulations to Don!

Wednesday, March 16th, 2005. All the numbers up to x = 90 inclusively had been completely factored.

Wednesday, March 16th, 2005. A serious bug in the ECM client was fixed, so please upgrade the program.

Friday, March 4th, 2005. The number of the composites was reduced to 3000.

Monday, February 28th, 2005. This month was amazing. 112 factorizations were reported, and most of the numbers were taken from the wanted list, while all remaining composites with x < 91 became reserved. Therefore 56 new composites (x from 91 to 95) were added to the wanted list. If all these additions had been made at once in the beginning of the year, there would have been 274 (!) wanted numbers. But, you see, almost a half of them had been factored just in two months.

Monday, February 28th, 2005. GMP-ECM 6.0 was released. This version has many improvements, e.g. speed-up in step 2 (especialy for large values of B2).

Wednesday, February 23th, 2005. The XYYXF Yahoo! group was created for our contributors. Welcome!

Monday, February 7th, 2005. Three days passed, and suddenly Hartmut Bock factored 108¹⁰⁰ + 100¹⁰⁸ making a seven-digit improvement to his recent P-1 result. This huge P49 divisor became the 4th largest prime factor found so far by P-1 method in the world.

Monday, February 7th, 2005. All the numbers with y < 11 had been completely factored.

Friday, February 4th, 2005. Hartmut Bock completed the factorization of 108⁵² + 52¹⁰⁸ with P-1. He found a large 42-digit prime factor which hit the first line in our P-1 records table.

Tuesday, February 2nd, 2005. A massive SNFS attack caused me to change my decision about the wanted list. So, 38 new numbers appeared there, it should be enough.

Friday, January 28th, 2005. An SNFS task, at 152 decimal digits, was successfully completed by Samuel Chong using GGNFS. To say the truth, the project was really reanimated due to this excellent software written by Chris Monico.

Wednesday, January 13th, 2005. The ECM client was updated to version 2.5.6 released by Mark Rodenkirch on the 3rd of January. Please download the new version and use it instead of an old one.

Thursday, December 30th, 2004. The set of wanted composites was extended to 180 numbers to provide wider choice for ECM and GNFS tasks. The list became too long, but I thought I wouldn't add more until 2006.

Monday, December 27th, 2004. The e-mail address of the project was changed due to some technical problems. Please use the new address: XYYXF@mail.by.

Monday, December 13th, 2004. The composite number of 130 digits was factored by Sean A. Irvine in 10 days with GNFS. Thus Sean completed the factorization of 87⁸⁰ + 80⁸⁷ and established a new GNFS record yet another time.

Tuesday, November 23rd, 2004. An alternative SIQS program, MSieve by Jason S. Papadopoulos, began to be used by our contributors. Version 0.83 was released and appeared to be quite fast, especially on AMD processors.

Wednesday, November 17th, 2004. A new open-source GNFS implementation, GGNFS by Chris Monico, had been quickly developed. The program became faster and more stable (GGNFS 0.70.0 was the latest version by the moment). Feel free to join the GGNFS Yahoo! group where you can help to test this software and to discuss it with other users.

Tuesday, July 6th, 2004. Paul Leyland's page Primes and PRPs of the form x^y + y^x (as well as other pages from Paul's site) was moved to the new location: http://www.leyland.vispa.com/numth/primes/xyyx.htm.

Thursday, May 20th, 2004. Sean A. Irvine, the main record holder of our project, completed the factorization of 86⁶⁹ + 69⁸⁶, the last number with x under 87, using GNFS method. It took 11 days to split the 124-digit composite cofactor establishing a new GNFS record. It must be also noted that this entry completed the Top-20 of GNFS records, so the total number of record entries reached 100, and therefore, in the end, all five record tables became filled. And since we have so many great news in one day, let me add another one, altough it's a bit off-topic... There was a birthday of my little niece Svetlana, she was two! :)

Saturday, March 27th, 2004. Hartmut Bock took all remaining composites (i.e. with x < 101) to run P±1 tests with B1 = 1G.

Thursday, February 5th, 2004. Richard Heylen started running P±1 tests using B1 = 1G over all XYYXF composites with x > 100 and quickly found a 42-digit prime factor of 136¹⁰⁷ + 107¹³⁶, setting a new P-1 record.

Thursday, December 11th, 2003. All the numbers up to x = 85 inclusively had been completely factored.

Friday, November 7th, 2003. Paul Zimmermann and Alexander Kruppa reported a bug in GMP-ECM which makes versions 5.0, 5.0.1 and 5.0.2 miss some factors. Please upgrade your version of GMP-ECM to 5.0.3 (or newer).

Monday, November 3rd, 2003. Greg Childers discovered some new algebraic factorizations of x^y + y^x using Mathematica. Namely, he factored y = 35 and 77 for x = 112; x = 133 and 147 for y = 112; x = 115 and 145 for y = 100 as well as the following pairs (x, y): (150, 24); (133, 28); (133, 76) and (147, 36). If the corresponding composites were factored with sieving methods, it would have taken weeks of CPU time.

Saturday, August 23rd, 2003. The number of the composites was reduced to 3500.

Monday, August 18th, 2003. Richard Heylen finished P±1 tests with B1 = 100M for all composites.

Friday, May 9th, 2003. The Top-20 of P±1 factors was quickly filled by Richard Heylen and several other contributors.

Sunday, April 27th, 2003. Greg's server finished running ECM with B1 = 250000.

Sunday, April 13th, 2003. Sean A. Irvine factored a 123-digit composite in 6 days, making a new GNFS record.

Thursday, April 10th, 2003. The XYYXF project lost several contributors because of the war against Iraq.

Tuesday, April 8th, 2003. Richard Heylen hit the 5th place in the world with 41-digit prime factor of 104⁷⁵ + 75¹⁰⁴, found by Pollard's P-1 method.

Tuesday, March 25th, 2003. Nicolas Daminelli found a 38-digit prime factor with Williams' P+1 method. This was the second largest factor found by this method in the world.

Wednesday, March 19th, 2003. The XYYXF project was extended up to x = 150. In total, 3534 new composites were added. All non-reserved composites with x > 100 passed ECM tests with B1 = 250000.

Friday, March 14th, 2003. GNFS became popular: Don Leclair factored a 115-digit number in 10 days.

Monday, February 24th, 2003. The new version of GMP-ECM program was released. A lot of new features were added in version 5.0, such as P±1 implementations and much faster B2 stage. Great thanks to Paul Zimmermann, Alexander Kruppa, Jim Fougeron and many other GMP-ECM contributors.

Friday, February 21st, 2003. Two days passed, and Sean A. Irvine improved his own GNFS result yet again, one digit longer and one day quicker. By the way, that new top-GNFS number became larger than the top-QS one.

Wednesday, February 19th, 2003. Sean A. Irvine improved his own GNFS record up to 113-digit composite, which took 6 days to be factored.

Sunday, January 5th, 2003. All the numbers up to x = 80 inclusively had been completely factored.

Thursday, December 26th, 2002. The number of composites with x < 101 was reduced to 300.

Friday, December 13th, 2002. Pierrick Gaudry found a 55-digit prime factor with ECM. This was the largest GMP-ECM factor found that year, and the second largest at all.

Wednesday, November 27th, 2002. The final pre-factoring stage was started on the numbers with 100 < x < 151. Greg Childers and Paul Leyland took the most of numbers to help.

Tuesday, October 22nd, 2002. The largest XYYXF composite, 188-digit number 98⁸¹ + 81⁹⁸, was factored by Paul Leyland with SNFS, yielding a 79-digit prime factor. Sieving took more than a month with the power of up to 32 CPU's. Several CPU-days were necessary to run the filtering stage and to produce the matrix of the size about 3Mx3M. Linear algebra was done on a single machine in 20 days and took 793 Mb of RAM. Finally, the square root stage just in an hour completed this great job. Paul's SNFS record will stay on the 1st place until the project is extended and somebody choose a larger number to beat it.

Sunday, September 15th, 2002. And yet greater SIQS result: the 114-digit cofactor of 80⁶⁹ + 69⁸⁰ was factored by Don Leclair in 2 weeks.

Thursday, August 29th, 2002. The Top-20 of ECM records was completely filled. Greetings went out to Greg Childers, Pierrick Gaudry and many other contributors.

Friday, August 23rd, 2002. Andrey Kulsha started factoring XYYXF numbers up to x = 150.

Friday, August 23rd, 2002. Sean A. Irvine obtained the first GNFS factorization for XYYXF project. It took 2 days to factor this 111-digit composite using Jens Franke's GNFS implementation.

Monday, August 19th, 2002. All the numbers up to x = 75 inclusively had been completely factored.

Friday, July 19th, 2002. The number of the composites was reduced to 400.

Tuesday, July 16th, 2002. New pretty MPQS result from Sean A. Irvine: a 112-digit giant halved in 6 days.

Wednesday, July 10th, 2002. And the Top-20 of largest QS-factored XYYXF composites was also filled. Most of the records belongs to Don Leclair whose SIQS implementation is quite fast.

Tuesday, July 2nd, 2002. Don Leclair broke Sean's old QS record: the factorization of 109-digit composite with SIQS took 5 days.

Tuesday, June 25th, 2002. The Top-20 of largest SNFS-factored XYYXF composites was filled completely, from 1st rank to 20th. Thanks to Sean A. Irvine for his great SNFS effort.

Friday, June 21st, 2002. All the numbers up to x = 70 inclusively had been completely factored.

Tuesday, May 28th, 2002. The number of the composites was reduced to 500.

Wednesday, May 15th, 2002. And another ECM record by Pierrick Gaugry: he extracted a huge 48-digit prime factor from 69³² + 32⁶⁹. This GMP-ECM factor appeared to be the largest one found so far in 2002.

Sunday, April 21st, 2002. Previous ECM record was broken by Greg Childers who found a 46-digit prime factor of 90⁸⁸ + 88⁹⁰.

Monday, April 8th, 2002. Andreas Enge extracted a 44-digit prime factor from 83⁶⁵ + 65⁸³ with ECM.

Saturday, March 30th, 2002. The number of the composites was reduced to 600.

Monday, March 25th, 2002. Using Tim Charron's software, Greg Childers made up an ECM server to factor XYYXF composites. Now you may run an ECM client and do some work without having to reserve particular numbers. For more information, see readme.txt included in the archive. Please also note that there's only the client, and it needs the program such as GMP-ECM to run ECM curves.

Sunday, March 24th, 2002. Jens Franke released the new version of his excellent MPQS implementation for Linux which is believed to be yet faster than PPSIQS. It was tested with numbers having up to 124 digits.

Tuesday, March 19th, 2002. All the numbers up to x = 60 inclusively had been completely factored.

Sunday, March 17th, 2002. And yet another fascinating record: Joe Leherbauer broke a 162-digit monster just in 4 days.

Wednesday, March 13th, 2002. New SNFS record came from Paul Leyland: in 14 days he managed to crack a C156 giant.

Wednesday, March 13th, 2002. The number of the composites was reduced to 750.

Sunday, March 3rd, 2002. This time Sean A. Irvine factored a 107-digit number in 29 hours with MPQS.

Wednesday, February 27th, 2002. First composite was cracked with SNFS method by Joe Leherbauer. It took 24 hours to split this 132-digit number on 1GHz Athlon.

Tuesday, February 26th, 2002. Sean A. Irvine joined the project and immediately broke Paul's QS record: a 102-digit composite was factored in 14 hours.

Monday, February 25th, 2002. The XYYXF project was announced!

Saturday, February 23rd, 2002. First ECM record: Paul Leyland found a 42-digit prime factor of 100⁹¹ + 91¹⁰⁰.

Thursday, February 21st, 2002. First huge factorization appeared on Records page. It took just 12 hours to factor a 100-digit composite with MPQS, using all 32 CPU's in Paul Leyland's cluster.

Sunday, January 27th, 2002. The number of the composites was reduced to 1000.

Friday, December 28th, 2001. Paul Leyland became the first contributor of XYYXF and greatly speeded up factoring process with the help of several machines.

Friday, November 23rd, 2001. All the numbers up to x = 100 were involved into factoring process.

Wednesday, November 14th, 2001. All the numbers up to x = 50 inclusively had been completely factored.

Friday, November 9th, 2001. Satoshi Tomabechi released the new version of PPSIQS which works faster than previous.

Tuesday, October 30th, 2001. Andrey Kulsha started factoring numbers of the form x^y + y^x for x < 61 on his slow AMD K6-233...