PrimeGridʼs27121 Prime Search
On 28 Feb 2012, 15:51:22, PrimeGrid’s 27121 Prime Search, through PRPNetand in collaboration with the 12121 Search (k=27 sister project), has found themega prime:
27*23855094-1
The prime is 1,160,501 digits long and will enter Chris Caldwell's “The Largest
Known Primes Database” (http://primes.utm.edu/primes) ranked 34th overall.
This is PrimeGrid’s 23rd mega prime.
The discovery was made by Pietari Snow of Finland using an Intel Xeon E5410@ 2.33GHz with 12GB RAM, running Microsoft Windows Server 2003 x64. This
computer took just over 4 hours 13 minutes to complete the primality test using
LLR. Pietari is a member of the PrimeSearchTeam.
The prime was verified on 28 Feb 2012, by an Intel Core i7 2600k @3.4Ghz
with 8 GB RAM, running Windows 7 x64. This computer took a little over 1
hours 25 minutes to complete the primality test using LLR x64 AVX.
Credits for the discovery are as follows:
1. Pietari Snow (Finland), 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
Entry in “The Largest Know Primes Database” can be found here:
http://primes.utm.edu/primes/page.php?id=105209
PrimGrid’s 27121 Prime Search is a collaboration with the 12121 Search, which
was established on 5/24/2004 to search for large primes of the form 121*2^n-1.
Later, on 3/1/2005, they added k=27 to their search. Their "short term" goal is tosearch for n up to 10M. PrimeGrid added the +1 form and searches both k’sand forms together.
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 whocontributed their advice and/or computing power to the search - especially all
the sievers who work behind the scenes to make a find like this possible.
This is PrimeGrid’s 23rd mega prime. The 27121 Prime Search will continue toseek even larger primes. To join the search please visit PrimeGrid:
http://www.primegrid.com

PrimeGridʼs27121 Prime Search
About PrimeGridPrimeGrid is a distributed computing project, developed by Rytis Slatkevičius,Lennart Vogel, and John Blazek, which utilizes BOINC and PRPNet to searchfor primes. PrimeGrid's primary goal is to bring the excitement of prime finding
to the "everyday" computer user. Simply download the software and let yourcomputer do the rest. Participants can choose from a variety of prime forms tosearch. With a little patience, you may find a large or even record breaking
prime.
BOINCThe 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 toastronomy. For more information, please visit BOINC:
http://boinc.berkeley.edu
PRPNet
PRPNet is a client/server application written by Mark Rodenkirch that is
specifically designed to help find prime numbers of various forms. It iseasily 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 primesearch projects, please visit: http://www.primegrid.com