English | Italian | Russian |

 

 

New Fermat factor from PrimeGrid!
57 . 2^2747499+1 is a Factor of   F_2747497!!!
Marshall Bishop & PrimeGrid found this giant Fermat factor less than a week after Ryan Propper.
He used LLR program for his discovery.
Congratulations to Marshall and PrimeGrid for the 5rd factor of the year!
- Ryan Propper found a new factor!
5449229488169 . 2⁴⁶⁵+1 is a Factor of   F₄₅₉!!!
Less than 4 months after the last discoveries, Ryan Propper broke the dry spell and found his first factor a few weeks after joining FermatSearch.
He used "a 100 core Linux cluster" and GMP-Fermat by Mark Rodenkirch for his discovery.
Congratulations from the team of FermatSearch for the 4rd factor of the year!
- PFGW 3.7.5 released
Mark Rodenkirch released a newer version of PFGW for Linux, MAC and Windows.
This new release corrects a bug on the GFN and xGF factoring.
Please visit the downlod page and update your older version now.
- PFGW 3.7.3 released
Mark Rodenkirch released a newer version of PFGW for Linux, MAC and Windows.
This new release has all the innovations of the last GWNUM library, and corrects some bugs on the Win 32-bit version.
Please visit the downlod page and update your older version now.
- Roman Maznichenko strikes again!
303472680883 . 2⁴²⁰+1 is a Factor of   F₄₁₇!!!
After the "four-factors-in-a-row" from Serge Batalov, Roman Maznichenko found 2 new factors in less than 24 hours.
This time he used an AMD FX-8350 @4000MHz and GMP-Fermat by Mark Rodenkirch for his test.
Congratulations from the team of FermatSearch for his 4th factor, the 3rd of the year! (Now we all ask for more...)
- Roman Maznichenko found his 3rd factor!
1210895760431083 . 2⁶⁸+1 is a Factor of   F₆₅!!!
Maxi found the factor using mmff and his Nvidia GTX 580, it the 2nd factor of this year.
He reached his goal after 5 months of continuous search.
Congratulations Roman!
- Maximilian Pacher found his 5th factor!
406860969 . 2³³²²+1 is a Factor of   F₃₃₁₄!!!
Maxi found the 309th factor of a Fermat number, the 1st factor of this year.
He used NewPGen, PRP and WinPFGW for his test.
Congratulations from the team of FermatSearch!
- Serge Batalov found his 4th factor this year!
10111717305 . 2¹¹³⁶+1 is a Factor of   F₁₁₃₂!!!
Serge Batalov found the 308th factor of a Fermat number. and the 16th this year.
He used GMP-Fermat.exe by Mark Rodenkirch for his testing of the range 1000 ≤ N ≤ 1199, 6,000,000,000 ≤ k ≤ 20,000,000,000.
Congratulations from the team of FermatSearch!
- New release of mmff!
George Woltman released mmff v0.27, a program written to test Fermat and Double Mersenne numbers using the power of GPU: it can now test numbers between F₂₆ and F₁₇₄!!!
Go and check it on the download page!
- Another Fermat factor found!!!
2864929972774011 . 2⁴¹+1 is a Factor of   F₃₉!!!
Tapio Rajala of Finland found his third Fermat factor, the 307th factor discovered.
Tapio found the factor using the new mmff.exe program written by George Woltman, optimized for nvidia GPUs.
It is the first factor discovered with mmff.exe!
Congratulations, Tapio!
- Serge strikes again! Found a third new Fermat factor after only 8 days!!!
3860269 . 2¹⁷⁷⁵⁰+1 is a Factor of   F₁₇₇₄₈!!!
Serge Batalov found his third Fermat factor, the 306th factor discovered.
Serge had access to a big computer farm, and with big effort and a little luck discovered another gem.
This year has been the richest in factors found since the release of Leonid Durman's 'Factor.exe, 2001, and the start of FermatSearch project. Serge, leave some factors to us!
- New Fermat factor after only 4 days!
30967 . 2¹⁰⁶⁴³⁶+1 is a Factor of   F₁₀₆₄₃₂!!!
Serge Batalov found another big factor, his second, and the 305th factor discovered.
Serge Batalov used NewPGen.exe by Paul Jobling for sieving and pfgw.exe for PRP test and xGFN divisibility test.
Congratulations from the team of FermatSearch!
- Found a new Fermat factor!
5505161 . 2⁹⁴⁴⁹+1 is a Factor of   F₉₄₄₇!!!
The factor was discovered by Serge Batalov of USA, it is his first Fermat factor, and the 304th factor discovered.
Serge Batalov used NewPGen.exe by Paul Jobling for sieving and pfgw.exe for PRP test and xGFN divisibility test.
Congratulations Serge!
- Vacation!!!
After more than 14 month of hard work, I will finally enjoy a pause from Nov. 2nd to Nov. 26th..
If you are close to finishing a range, or just need to reserve some more work for next month, please do it now.
Reservations and results will be gathered as usual on a first-come, first served base. Ranges come after Nov. 1st won't get lost, but will be delayed until I come back home to assign them.
- Found a new Fermat factor!
143918649 . 2⁴⁶⁵⁴+1 is a Factor of   F₄₆₅₂!!!
The factor was discovered by Tapio Rajala of Finland, it is his second Fermat factor, and the 303rd factor discovered.
Tapio Rajala used NewPGen.exe by Paul Jobling for sieving and pfgw.exe for PRP test and xGFN divisibility test.
Congratulations from the team of FermatSearch!
- New fast program to test Fermat numbers!
George Woltman, head of GIMPS and programmer of Prime95, the fastest code to test Mersenne numbers, developed and released mmff, a program written to test Fermat and Double Mersenne numbers using the power of GPU: it is more than 50 times faster than any other program for numbers between F₂₆ and F₁₄₅!!!
Go and check it on the download page!
- New Fermat factor found!
72179955 . 2⁴²⁶⁹+1 is a Factor of   F₄₂₆₅!!!.
The factor was discovered by Takahiro Nohara of Japan, it is his ninth Fermat factor, and the 302nd factor discovered.
Takahiro Nohara used NewPGen.exe by Paul Jobling for sieving and OpenPFGW.exe for PRP test and xGFN divisibility test.
Congratulations from the team of FermatSearch!
- New Fermat factor after 3 days!
2674670937447 . 2¹⁷¹+1 is a Factor of   F₁₆₆!!!.
The factor was discovered by Roman Maznichenko from Russia using a AMD FX-8120 @3800MHz and his version of Mark Rodenkirch's GMP-Fermat. This is the fourth factor found by GMP-Fermat, and the second found by Roman Maznichenko.
We have discovered 9 factors in less than 7 months, the same total of the whole 2011, and we keep going!
Congratulation from FermatSearch, Roman!
- 300th Fermat factor found!
20018578522347 . 2⁸⁸+1 is a Factor of   F₈₆!!!.
The factor was discovered by Michael Dangler of USA, using Mark Rodenkirch's program GMP-Fermat, and is the eighth factor discovered this year.
The factor was found using this environment:

• Windows 7 Home Premium 64-bit Operating System
• Toshiba Satellite P775
• Intel(R)Core(TM)i7-2670QM CPU @2.20GHZ 6.00 GB Memory

Michael found the factor on its eleventh test-range, after only a few months of testing.
Congratulations from the team of FermatSearch!
- New Fermat factor found!
262254673 . 2³⁷⁰⁶+1 is a Factor of   F₃₇₀₃!!!.
The factor was discovered by Takahiro Nohara of Japan, it is his eighth Fermat factor, and the seventh factor discovered this year.
Takahiro Nohara used NewPGen.exe by Paul Jobling for sieving and OpenPFGW.exe for PRP test and xGFN divisibility test.
Congratulations from the team of FermatSearch!
- Sixth Fermat factor of 2012!
On June 13th, 2012, and as part of PrimeGrid's Proth Prime Search, Robert Boniecki found the following new factor of a Fermat number: 1705 . 2⁹⁰⁶¹¹⁰+1 is a Factor of   F₉₀₆₁₀₈!!!.
The number has 272770 digits and is the 298th Fermat factor discovered. Will we be able to reach 300 factors by the end of the year? The credits for the discovery are as follows:
   1. Robert Boniecki, discoverer
   2. PrimeGrid, et al.
   3. Srsieve, sieving program developed by Geoff Reynolds
   4. PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
   5. LLR, primality program developed by Jean Penné
   6. OpenPFGW, a primality program developed by Chris Nash & Jim Fougeron with maintenance and improvements by Mark Rodenkirch
Congratulations go to Robert and to the leading organizers of PrimeGrid!
- Fifth Fermat factor of 2012!
On May 31, 2012, and as part of PrimeGrid's Proth Prime Search, James Boerner found the following new factor of a Fermat number: 7905 . 2³⁵²²⁸¹+1 is a Factor of   F₃₅₂₂₇₉!!!.
The credits for the discovery are as follows:
   1. James Boerner, discoverer
   2. PrimeGrid, et al.
   3. Srsieve, sieving program developed by Geoff Reynolds
   4. PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
   5. LLR, primality program developed by Jean Penné
   6. OpenPFGW, a primality program developed by Chris Nash & Jim Fougeron with maintenance and improvements by Mark Rodenkirch
Congratulations go to James and to the leading organizers of PrimeGrid!
- FermatSearch strikes again!
4785972759 . 2⁹⁵⁴+1 is a Factor of   F₉₄₃!!!.
The factor was discovered by Andriy Sen of Ukraine, and is the fourth factor of this year.
He used GMP-Fermat.exe on a Windows Server 2008 R2 Standard x64, Intel Core2 CPU 6600 @ 2.40 GHz to test it. Andriy found his factor while testing N=900-989 and k=4,000,000,000-5,000,000,000.
Congratulations from the team of FermatSearch!
- Seventh Fermat factor found by Takahiro Nohara!
238451805 . 2²⁶⁰⁸+1 is a Factor of   F₂₆₀₆!!!.
The factor was discovered by Takahiro Nohara of Japan, and is the third factor of this year.
He used NewPGen.exe by Paul Jobling for sieving and OpenPFGW.exe for PRP test and xGFN divisibility test. Takahiro found his factor while testing N=2005-2999 and k=60,000,000-400,000,000 exactly on the first anniversary of the earthquake and tsunami disaster that triggered also a nuclear accident in Fukushima.
Congratulations from the team of FermatSearch!
- Second Fermat factor of 2012!
On 4 Jan 2012 0:34:57 UTC, PrimeGrid's Proth Prime Search project found a prime Fermat divisor: 131 . 2^1494099+1 is a Factor of   F_1494096!!!.
The prime is 449,771 digits long and will enter Chris Caldwell's "The Largest Known Primes Database" ranked 6th for prime Fermat divisors and 292nd overall. It is the 2nd divisor found in 2012 and 294th overall.
The discovery was made by Rob Derrera of the United States using an Intel Core i7 960 @ 3.20GHz with 24 GB RAM running Windows 7 Ultimate x64. This computer took just over 53 minutes to complete the primality test using LLR. Rob is a member of the US Navy team.
The prime was verified on 7 Feb 2012, 4:56:41 UTC, by Sergey Iovov of the Ukraine using an Intel Xeon X5650 @ 2.67GHz with 24 GB RAM running Windows Server 2008 Standard x64. This computer took 53 minutes 45 seconds to complete the primality test using LLR. The credits for the discovery are as follows:
   1. Rob Derrera (United States), discoverer
   2. PrimeGrid, et al.
   3. Srsieve, sieving program developed by Geoff Reynolds
   4. PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
   5. LLR, primality program developed by Jean Penné
   6. OpenPFGW, a primality program developed by Chris Nash & Jim Fougeron with maintenance and improvements by Mark Rodenkirch
Congratulations go to Rob and to the leading organizers of PrimeGrid!
- First Fermat factor of 2012!
On 4 Jan 2012 0:34:57 UTC, PrimeGrid's Proth Prime Search project found a prime Fermat divisor: 329 . 2^1246017+1 is a Factor of   F_1246013!!!.
The prime is 375,092 digits long and will enter Chris Caldwell's "The Largest Known Primes Database" ranked 6th for prime Fermat divisors and 522nd overall. It is the 1th divisor found in 2012 and 293rd overall.
The discovery was made by Bruce Dodson of the United States using an Intel Xeon MP @ 2.80GHz with 12 GB RAM running Linux. This computer took just over 3 hours and 25 minutes and 28 seconds to complete the primality test using LLR. Grzegorz is a member of the Sicituradastra Team.
The prime was verified on 6 January 2012 17:41:07 UTC, by Ovidiu Cioca of Canada using an Intel Core2 6700 @ 2.66GHz with 4 GB RAM running Windows XP. This computer took 29 minutes and 45 seconds to complete the primality test using LLR.
The credits for the discovery are as follows:
   1. Bruce Dodson (United States), discoverer
   2. PrimeGrid, et al.
   3. Srsieve, sieving program developed by Geoff Reynolds
   4. PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
   5. LLR, primality program developed by Jean Penné
   6. OpenPFGW, a primality program developed by Chris Nash & Jim Fougeron with maintenance and improvements by Mark Rodenkirch
Congratulations go to Bruce and to the leading organizers of PrimeGrid!
- Nine Fermat factors found in 9 months! Will we be able to reach 12 this year?
On 9 Sep 2011 11:50:50 UTC, PrimeGrid's Proth Prime Search project found a prime Fermat divisor: 25 . 2^2141884+1 is a Factor of   F_2141872!!!.
The prime is 644,773 digits long and will enter Chris Caldwell's "The Largest Known Primes Database" ranked 5th for prime Fermat divisors and 88th overall. It is the 9th divisor found in 2011 and 292nd overall.
The discovery was made by Grzegorz Granowski of Poland using an Intel Xeon X5550 @ 2.67GHz with 12 GB RAM running Windows Vista x64. This computer took just over 58 minutes and 28 seconds to complete the primality test using LLR. Grzegorz is a member of the Polish National Team.
The prime was verified on 11 Sep 2011 12:02:18 UTC, by John R. H. Graham of Canada using an Intel i7 920 @ 2.67GHz with 12 GB RAM running Windows 7 x64. This computer took about 1 hour and 47 minutes to complete the primality test using LLR. John is a member of Team Canada.
The credits for the discovery are as follows:
   1. Grzegorz Granowski (Poland), discoverer
   2. PrimeGrid, et al.
   3. Srsieve, sieving program developed by Geoff Reynolds
   4. PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
   5. LLR, primality program developed by Jean Penné
   6. OpenPFGW, a primality program developed by Chris Nash & Jim Fougeron with maintenance and improvements by Mark Rodenkirch
Congratulations go to Grzegorz and to the leading organizers of PrimeGrid!
- News from the download page!
New PFGW for Windows, MAC and Linux, and fermfact 2.0 added today.
- Another Fermat factor from PrimeGrid!
On 8th July 2011 02:22:20 UTC, PrimeGrid's Proth Prime Search project, through PRPNet, found a prime Fermat divisor: 4479 . 2²²⁶⁶¹⁸+1 is a Factor of   F₂₂₆₆₁₄!!!.
The prime is 68,223 digits long. It is the 8th divisor found in 2011 and 291th overall.
The discovery was made by Peter Doggart of the United Kingdom using an AMD Phenom 9600 X4 @ 2.3 GHz with 3 GB RAM running 32 bit Windows 7. This computer took 78 seconds to complete the primality test using LLR.
The credits for the discovery are as follows:
   1. Peter Doggart (United Kingdom), discoverer
   2. PrimeGrid, et al.
   3. Srsieve, sieving program developed by Geoff Reynolds
   4. PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
   5. LLR, primality program developed by Jean Penné
   6. OpenPFGW, a primality program developed by Chris Nash and Jim Fougeron with maintenance and improvements by Mark Rodenkirch
Congratulations go to Peter and to the leading organizers of PrimeGrid!
- Seven Fermat factors found in 7 months!
43714055 . 2³³³⁷+1 is a Factor of   F₃₃₃₅!!!.
The factor was discovered by Nikolay Kamenyuk of Ukraine, and is the seventh factor of this year. We now have 250 Fermat numbers known to be composite, and "10 to go" to reach 300 prime factors overall.
Nikolay found his factor while testing N=3001-4000 and k=40,000,000-100,000,000.
Congratulations Nikolay!
- PrimeGrid strikes again!
On 1 July 2011 02:59:41 UTC, PrimeGrid's Proth Prime Search project, through PRPNet, found a prime Fermat divisor: 3771 . 2²²¹⁶⁷⁶+1 is a Factor of   F₂₂₆₁₇₀!!!.
The prime is 66,736 digits long. It is the 6th divisor found in 2011 and 289th overall.
The discovery was made by Mark Doom of the United States using an AMD Phenom II X6 1090T with 2 GB RAM running Windows 7 x64. This computer took 40 seconds to complete the primality test using LLR.
The credits for the discovery are as follows:
   1. Mark Doom (United States), discoverer
   2. PrimeGrid, et al.
   3. Srsieve, sieving program developed by Geoff Reynolds
   4. PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
   5. LLR, primality program developed by Jean Penné
   6. OpenPFGW, a primality program developed by Chris Nash and Jim Fougeron with maintenance and improvements by Mark Rodenkirch
Congratulations go to Mark and to the leading organizers of PrimeGrid!
- New Fermat factor discovered after 1 day!
7333 . 2¹³⁸⁵⁶⁰+1 is a Factor of   F₁₃₈₅₅₇!!!.
The factor was discovered by Dirk D'huyvetters of Belgium coadiuvated by the PrimeGrid team. This is the 288th known divisor fifth factor found this year.
This factor was the first of the three disconvered in March, but only during the recent double-checking for GFN divisibilities the factor was revealed, as the team was focused on Proth Primes and not Fermat factors.
Congratulations go to Dirk and to the leading organizers of PrimeGrid: John Blazek, Rytis Slatkevičius and Lennart Vogel!
- New record-size Fermat factor!
As part of PrimeGrid's Proth Prime Search, Scott Brown (USA) found the following new factor of a Fermat number: 9 . 2^2543551+1 is a Factor of   F_2543548!!!.
This factor 765,687 digits long exceeds in size the prime factor 3 . 2^2478785+1 of   F_2478782 discovered on October 10, 2003 and therefore is currently the largest known divisor of a Fermat number!
Congratulations to everyone involved in this remarkable discovery!!
- New Fermat factor after 5 days!
111318179143061 . 2⁴⁵+1 is a Factor of   F₄₂!!!.
The factor was discovered by Roman Maznichenko from Russia using Mark Rodenkirch's GMP-Fermat. This is the first factor found by GMP-Fermat.
Roman worked hard on ECM also, and we all hope he will find another factor soon.
Congratulation, Roman!
- Second Fermat factor of 2011!
14783975791554494074552473179612897725474511 . 2¹⁹+1 is a Factor of   F₁₇!!!.
The factor was discovered by David Bessell from St Michael's Collegiate School in Australia using Prime95. This is the third factor found by David while computing ECM curves on small Fermat numbers.
The cofactor of F17 has around 39,000 digits, and has been proven composite.
Congratulation, David!
- FermatSearch.org has a new server ! To guarantee better performances to our users, your webmaster has taken the opportunity to upgrade the old hardware and install a new more powerful one. Please let me know about every possible glitch that may have occurred during the migration of data.
- GMP-Fermat 2.1 for Windows 64 bit version has passed its checks!!!.
Thanks to Matt Anderson (who addressed the issue on MersenneForum) and Brian Gladman (who offered his programming skills), we now finally have a GMP-Fermat version with superfast assembly routines written by Geoff Reynolds and running on Windows 64-bit platforms!
The new executable can be found on the Download page. Wonderful job, Brian and Matt, thank you!
- First Fermat factor of 2011!
837747239 . 2¹²⁰³+1 is a Factor of   F₁₂₀₁!!!.
The factor was discovered by our old friend Maximilian Pacher, from Austria, using NewPGen, PRP and PFGW programs. Maxi could have found this factor seven years ago if his range were not limited to 1200.
This is his fourth Fermat factor"
Congratulation, Maxi!
- GMP-Fermat 2.1 for Windows 64 bit version is out!!!.
Thanks to Matt Anderson (who addressed the issue on a forum) and Brian Gladman (who offered his programming skills), we now finally have a GMP-Fermat version with superfast assembly routines written by Geoff Reynolds and running on Windows 64-bit platforms!
The new executable can be found on the Download page. Wonderful job, Brian and Matt, thank you!
- A second new Fermat factor has been found on November 20!
272392805475 . 2³⁰⁴+1 is a Factor of   F₂₉₉!!!.
The factor was discovered by Alexey Komkov, from Russia, using his own program written in Borland C++ builder. Alexey has been testing a huge range using 30 P4 computers in the last 6 months.
Congratulation, Alexey!
- A totally new Fermat factor has been found!
103257279 . 2²⁴²²+1 is a Factor of   F₂₄₂₀!!!.
The factor was discovered by Peter Strasser, from Austria, on November 7th, 2010. Peter was testing a huge range with his own program based on Mathematica.
Congratulation, Peter!
- Five in a row! Michael Vang (USA) found a new Fermat factor: 17353230210429594579133099699123162989482444520899 . 2¹⁵+1 is a Factor of   F₁₂!!!.
Mike found this factor after 5200 curves ran on F12.
Software used: GMP-ECM 6.2. The cofactor is still composite.
He used two AMD Phenom X4 9550 quad core boxes with 6GiB RAM each, running on Debian Linux.
Congratulations Mike!
- Third Fermat factor from GIMPS! David Bessel found a new Fermat factor: 3853959202444067657533632211 . 2²⁴+1 is a Factor of   F₂₂!!!.
The factor has been discovered by David Bessell from St Michael's Collegiate School in Australia using Prime95, while testing some ECM curves on F22.
It is the seconf Fermat factor discovered by David Bessell in less than one year, after more than 15,500 GHz-Days.
The cofactor is still composite...
Congratulations to Mr. David Bessell!
- PFGW 3.3.3 for Windows, Linux and MAC is out!!!.
Mark Rodenkirch released another, faster, version of PFGW for Windows, Linux and MAC, based on v25.14 of gwnum library.
The major change in this release is that it has been updated to use gwnum 25.14, which addresses the following issues:
* Gwnum would lose the /d in some (k*b^n+c)/d cases. This happened primarily in cases where the number was between 300 and 350 bits.
* The final conversion from gwnum to binary could fail in cases where generic reduction was used. The larger the number the less likely the bug would occur.
* Zero padded FFTs of length 80 and 112 could fail.
* More conservative in selecting an FFT length for non-base-2 cases.
This release also goes back to using rational FFTs, which are slightly faster than irrational FFTs.
With these changes to gwnum, there will be fewer roundoff errors with PFGW. These changes also address primality tests that silently fail. "Silently fail" refers to tests that do not trigger roundoff errors, yet have an incorrect result. It is highly recommended to update your clients to this release.
The new executable can be found on the Download page. Wonderful job, Mark, thank you!
- Another factor comes from FermatSearch! Cedric Vonck found a new Fermat factor: 81909357657279 . 2⁵⁴+1 is a Factor of   F₅₂!!!.
Cedric found this factor while testing his first range, how lucky!
Software used: Fermat.exe
The new factor is the third Fermat factor discovered in 2010.
Congratulations to Mr. Cedric Vonck!
- GIMPS strikes again! Tapio Rajala (Department of Mathematics and Statistics - University of Jyväskylä, Finland) found a new Fermat factor: 1784180997819127957596374417642156545110881094717 . 2¹⁶+1 is a Factor of   F₁₄!!!.
Tapio found this factor after approximately 750 curves ran on F14 with B1=110M.
Software used: Prime95
Note that F14 was the first Fermat number without known factors. The cofactor, C4880, is composite.
The new factor is the second Fermat factor discovered in 2010, and the second discovered by GIMPS using Elliptic Curves Method.
Congratulations to Mr. Tapio Rajala!
- Sergei Maiorov found a new Fermat factor: 84977118993 . 2⁵²⁰+1 is a Factor of   F₅₁₇!!!.
"It's my first Fermat factor, and also the first one of 2010!"
Software used: Fermat.exe 4.4
Congratulations to Mr. Sergei Maiorov!
- PFGW 3.3.0 for Linux and MAC, and 3.3.1 for WIndows are out!!!.
Mark Rodenkirch released another, faster, version of PFGW for Windows, Linux and MAC, based on v25.13 of gwnum library.
The new executable can be found on the Download page. Wonderful job, Mark, thank you!
- PFGW 3.2.3 is out!!!.
Mark Rodenkirch released a new, enhanced and bug-free version of PFGW for Windows, Linux and MAC, based on v25.13 of gwnum library.
The new executable can be found on the Download page. Thank you Mark!
- Takahiro Nohara found a new Fermat factor: 1814649 . 2¹²⁸²⁷+1 is a Factor of   F₁₂₈₂₅!!!.
"After six month since my previous report of a factor of the Fermat number, I'm able to tell you following one.
I also accumulated dozens of xGFN factors since my previous report.
Software
Fermfact.exe for sieving
LLR.exe for proth test
pfgw.exe to test xGFN divisibility (with -a2 or -a1 switch)"
Congratulations to Mr. Takahiro Nohara!
- George Woltman announced today that a new factor of F19 has been found: 8962167624028624126082526703 . 2²²+1 is a Factor of   F₁₉!!!.
The factor has been discovered by David Bessell from St Michael's Collegiate School in Australia using Prime95, while testing some ECM curves on F19.
It's the first factor of a Fermat number of index < 30 since the turn of the century, and only the fourth of index < 80.
The 35 digits factor has been proven prime, a 157,770-digit composite cofactor remains. The cofactor has been proven composite by independent users, with different software.
The known factorization of F19 is now 70525124609.646730219521.37590055514133754286524446080499713.C157770 Congratulations to GIMPS distributed ECM effort!
- PFGW 1.3 for Windows is out!!!.
Mark Rodenkirch did the magic, and re-engineered PFGW with George Woltman's GWNUM 25.10 library.
The new executable can be found on the Download page. Enhancements to: v1.3 Release Candidate 1
- Updated to v25.10 of George Woltman's gwnum library
- Ported to MacIntel
- Addressed inconsistent handling of switches as some require parameters, some require parameters of specific values, and others have optional parameters
- Print leading zeros on residues so that they are always 16 characters
- Added -k for terse output, useful when running multiple files through PFGW in succession
- Takahiro Nohara strikes again! He found today the fourth Fermat factor of 2009:
71007 . 2⁴⁹⁴⁹⁰+1 is a Factor of   F₄₉₄₈₈!!!.
Takahiro found the factor and two new xGF factors too, using Fermfact for sienving, LLR for Proth tests and OpenPFGW for checking xGFN divisibily test.
Congratulations go to Takahiro Nohara!

 

Compiled by Luigi Morelli