PrimeGrid’s
Generalized Fermat Prime Search
On 22 March 2017, 09:33:58 UTC, PrimeGrid’s Generalized Fermat Prime Search found theGeneralized Fermat mega prime:2676404

262144+1

The prime is 1,684,945 digits long and enters Chris Caldwell's “The Largest Known Primes
thndDatabase” (http://primes.utm.edu/primes) ranked 5 for Generalized Fermat primes and 52overall.
The discovery was made by Wolfgang Schwieger of Germany using an NVIDIA GeForce GTX
1070 in an Intel(R) Core(TM) i7-6700K CPU at 4.00GHz with 16GB RAM, running Linux. ThisGPU took about 16 minutes to probable prime (PRP) test with GeneferOCL4. Wolfgang is amember of the SETI.Germany team.
The prime was verified on 22 March 2017, 23:16:34 UTC by William de Thomas of Puerto Ricousing an NVIDIA GeForce GTX Titan X in an Intel(R) Core(TM) i7-4790K CPU at 4.00GHz with
16GB RAM, running Microsoft Windows 10 Professional Edition. This GPU took about 18
minutes to probable prime (PRP) test with GeneferOCL4. William is a member of the Puerto Rico
Assisting Science team.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB
RAM, running Microsoft Windows 10 Professional. This computer took about 8 hours 40 minutes
to complete the primality test using LLR.
The credits for the discovery are as follows:
1.
2.
3.
4.
5.
6.

Wolfgang Schwieger (Germany), discoverer
PrimeGrid, et al.
AthGFNSieve, sieve program developed by David Underbakke
GFNSvCUDA , sieve program developed by Anand Nair
GeneferOCL, probable prime program developed by Yves Gallot
LLR, primality program developed by Jean Penné

Entry in “The Largest Known Primes Database” can be found here:
http://primes.utm.edu/primes/page.php?id=123187Using a single PC would have taken years to find this prime. So this timely discovery would nothave been possible without the hundreds of volunteers who contributed their spare CPU cycles. A
special thanks to everyone who offered their advice and/or computing power to the search especially Yves Gallot, Iain Bethune, David Underbakke, Anand Nair, Mark Rodenkirch and Geoff
Reynolds who were major forces in moving the project forward. Also, thank you to all the sievers,
especially Honza Cholt and Jim Breslin. A final thanks to Michael Goetz for porting to BOINC.
The Generalized Fermat Prime Search will continue to seek even larger primes. To join thesearch please visit PrimeGrid: http://www.primegrid.com

PrimeGrid’s
Generalized Fermat Prime Search
About PrimeGrid
PrimeGrid is a distributed computing project, developed by Rytis Slatkevičius and currentlymanaged by Iain Bethune, James Breslin, Scott Brown, Ulrich Fries, Charley Gielkens, MichaelGoetz, Roger Karpin, Rytis Slatkevičius, and Van Zimmerman.
PrimeGrid is hosted by RackSpace, and their generous contributions have helped make thisproject possible.
PrimeGrid utilizes BOINC and PRPNet to search for primes with the primary goal of bringing theexcitement of prime finding to the "everyday" computer user. Simply download the software andlet your computer do the rest. Participants can choose from a variety of prime forms to search.
With a little patience, you may find a large or even record breaking prime.
BOINC
The Berkeley Open Infrastructure for Network Computing (BOINC) is a software platform
for distributed computing using volunteered computer resources. It allows users toparticipate in multiple distributed computing projects through a single program. CurrentlyBOINC is being developed by a team based at the University of California, Berkeley led byDavid Anderson.
This platform currently supports projects from biology to math to astronomy. For more
information, please visit BOINC: http://boinc.berkeley.edu
PRPNet
PRPNet is a client/server application written by Mark Rodenkirch that is specificallydesigned to help find prime numbers of various forms. It is easily ported between various
OS/hardware combinations. PRPNet does not run each PRP test itself, but relies on helper
programs, such as LLR, PFGW, phrot, wwww, and genefer to do the work.
For more information, please visit PrimeGrid’s PRPNet forum thread:
http://www.primegrid.com/forum_thread.php?id=1215
For more information about PrimeGrid and a complete list of available prime search projects,
please visit: http://www.primegrid.com