PrimeGrid’s
321 Prime Search
On 6 September 2021, 07:16:28 UTC, PrimeGrid’s 321 Prime Search found another Mega Prime:3*217748034-1
The prime is 5,342,692digits long and will enter Chris Caldwell's “The Largest Known Primes
Database” (http://primes.utm.edu/primes) ranked 18th overall. This is the largest known prime forthe 3*2^n-1 form.
The discovery was made by Marc Wiseler of Ireland using an AMD Ryzen 9 5900X 12-Core
Processor with 16GB RAM, running Microsoft Windows 10 Professional x64 Edition. This
computer took about 2 hours, 45 minutes to complete the primality test using LLR. Marc Wiseler
is a member of Storm.
The prime was verified on 6 September 2021, 11:47 UTC, by an Intel(R) Core(TM) i7-9800X CPU@ 3.80GHz with 32GB of RAM, running CentOS. This computer took 2 hours and 41 minutes tocomplete the primality test using LLR2.
Credits for the discovery are as follows:
1.
2.
3.
4.
5.
6.

Marc Wiseler (Ireland), discoverer
PrimeGrid, et al.
Srsieve, sieving program developed by Geoff Reynolds
PSieve, sieving program developed by Ken Brazier and Geoff Reynolds
LLR, primality program developed by Jean Penné
LLR2, primality program developed by Pavel Atnashev

Entry in “The Largest Know Primes Database” can be found here:
https://primes.utm.edu/primes/page.php?id=132678

Using a single PC would have taken years to find this prime. So this timely discovery would nothave 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 the sievers who work behind the scenes to make a find like this possible.
The 321 Prime Search will continue to seek even larger primes. To join the search please visit
PrimeGrid: http://www.primegrid.com

PrimeGrid’s
321 Prime Search
About PrimeGrid
PrimeGrid is a distributed computing project, developed by Rytis Slatkevičius and currently
managed by Tyler Bredl, Scott Brown, Ulrich Fries, Michael Goetz, Michael Gutierrez, Dao Heng
Liu, Reginald McLean, Rytis Slatkevičius, Roman Trunov, and Christian Wallbaum.
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. Currently
BOINC 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

PRPNetPRPNet 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