Distributed Search for Fermat Number Divisors Project News

News and project updates which haven't been added to distributedcomputing.info yet.

Moderators: Jwb52z, CedricVonck, kpearson, Honza, Lupine1647

Postby CedricVonck » Tue Mar 16, 2010 9:37 pm

March 15, 2010
Another factor comes from FermatSearch! Cedric Vonck found a new Fermat factor: 81909357657279*2^54+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!
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Postby Jwb52z » Mon Mar 29, 2010 11:17 pm

March 27, 2010
Five in a row! Michael Vang (USA) found a new Fermat factor: 17353230210429594579133099699123162989482444520899 * 2^15+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!

March 26 2010
Third Fermat factor from GIMPS! David Bessel found a new Fermat factor: 3853959202444067657533632211 * 2^24+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!

March 26, 2010
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!
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Postby Jwb52z » Sun Jun 26, 2011 9:26 pm

June 23, 2011
New Fermat factor discovered after 1 day!
7333*2^138560+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!
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June 22, 2011
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 F2543548!!!.
This factor 765,687 digits long exceeds in size the prime factor 3* 2^2478785+1 of F2478782 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!!
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March 20, 2011
New Fermat factor after 5 days!
111318179143061*2^45+1 is a Factor of F42!!!.
The factor was discovered by Roman Maznichenko from Russia using Mark Rodenkirch's GMP-Factor. This is the first factor found by GMP-Factor.
Roman worked hard on ECM also, and we all hope he will find another factor soon.
Congratulation, Roman!
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March 15, 2011
Second Fermat factor of 2011!
14783975791554494074552473179612897725474511*2^19+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!
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February 21, 2011
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.
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February 5, 2011
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!
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January 12, 2011
First Fermat factor of 2011!
837747239*2^1203+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!
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December 9, 2010
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, http://www.fermatsearch.org/download.html , page. Wonderful job, Brian and Matt, thank you!
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November 20, 2010
A second new Fermat factor has been found on November 20!
272392805475*2^304+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!
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November 8, 2010
A totally new Fermat factor has been found!
103257279*2^2422+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!
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Postby Jwb52z » Mon Jul 04, 2011 7:08 pm

July 1, 2011
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*2^221676+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!
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