PrimeGrid’s
Proth Prime Search
On 08 July 2011 02:22:20 UTC, PrimeGrid's Proth Prime Search project, through
PRPNet, found a prime Fermat divisor:4479*2226618 +1 Divides F(226614)
The prime is 68,223 digits long. It is the 8th divisor found in 2011 and 291stoverall.
The discovery was made by Peter Doggart of the United Kingdom using an AMD
Phenom 9600 X4 @ 2.3GHz with 3 GB RAM running 32 bit Windows 7. This
computer took 78 seconds to complete the primality test using LLR. Peter is amember of the PrimeSearchTeam.
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 & Jim
Fougeron with maintenance and improvements by Mark Rodenkirch
Fermat number divisibility (including generalized and extended) was checked byOpenPFGW using the following settings: -gxo –a2 4479*2^226618+1. For more
information about Fermat and generalized Fermat number divisors, please see
Wilfrid Keller's sites:

http://www.prothsearch.net/fermat.html
http://www1.uni-hamburg.de/RRZ/W.Keller/GFNfacs.html

There were no generalized or extended generalized Fermat number divisors.
Using a single PC would have taken years to find this prime. So this timely
discovery would not have been possible without the thousands of volunteers who
contributed their spare CPU cycles. A special thanks to everyone who
contributed their advice and/or computing power to the search - especially all thesievers who work behind the scenes to make a find like this possible.
This is PrimeGrid’s 7th prime Fermat divisor. The Proth Prime Search willcontinue to search for more primes. To join the search please visit PrimeGrid:
http://www.primegrid.com

PrimeGrid’s
Proth Prime Search
About PrimeGrid
PrimeGrid is a distributed computing project, developed by Rytis Slatkevičius,Lennart Vogel, and John Blazek, which utilizes BOINC and PRPNet to search forprimes. PrimeGrid's primary goal is to bring the excitement of prime finding to the"everyday" computer user. Simply download the software and let your computer
do the rest. Participants can choose from a variety of prime forms to search. Witha little patience, you may find a large or even record breaking prime.
BOINC
The Berkeley Open Infrastructure for Network Computing (BOINC) is asoftware platform for distributed computing using volunteered computerresources. It allows users to participate in multiple distributed computing
projects through a single program. Currently BOINC is being developed bya team based at the University of California, Berkeley led by David
Anderson.
This platform currently supports projects from biology to math to astronomy.
For more information, please visit BOINC: http://boinc.berkeley.edu
PRPNetPRPNet is a client/server application written by Mark Rodenkirch that is
specifically designed 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, and genefer to do the work.
For more information, please visit PrimeGrid’s PRPNet forum thread:
http://www.primegrid.com/forum_thread.php?id=1215For more information about PrimeGrid and a complete list of available primesearch projects, please visit: http://www.primegrid.com