PrimeGrid’sSeventeen or Bust SubprojectOn 31 October 2016, 22:13:54 UTC, PrimeGrid’s Seventeen or Bust subproject found the Mega
Prime:31172165
10223*2+1
The prime is 9,383,761 digits long and will enter Chris Caldwell's “The Largest Known Primes
thDatabase” (http://primes.utm.edu/primes) ranked 7 overall.
This is the largest prime found attempting to solve the Sierpinski Problem and eliminates
k=10223 as a possible Sierpinski number. It is also the largest known Proth prime, the largest
known Colbert number (http://mathworld.wolfram.com/ColbertNumber.html) , and the largest
prime PrimeGrid has discovered. Among the 10 largest known prime numbers, it is the only
prime that is not a Mersenne number, and the only known non-Mersenne prime over 4 million
digits.
Until the Seventeen or Bust project shut down earlier in the year, this search was acollaboration between PrimeGrid and Seventeen or Bust. This discovery would not have beenpossible without all the work done over the years by Seventeen or Bust.
The discovery was made by Szabolcs Peter of Hungary using an Intel(R) Core(TM) i7-4770CPU @ 3.40GHz with 12GB RAM, running Microsoft Windows 10 Enterprise Edition. This
computer took about 8 days, 22 hours, 34 minutes to complete the primality test using LLR.
The prime was verified on 29 November 2016, 05:45:19 UTC by Heidi Kohne of the UnitedStates using an AMD A6-3600 APU with 6GB RAM, running Microsoft Windows 7 HomePremium. This computer took about 27 days, 7 hours, 33 minutes to complete the primality test
using LLR.
Credits for the discovery are as follows:
1.
2.
3.
4.
5.
6.
7.
8.
9.

Szabolcs Peter (Hungary), discoverer
PrimeGrid, et al.
Seventeen or Bust, et al.
SoBSieve, sieving program developed by Paul Jobling
ProthSieve, sieving program developed by Mikael Klasson and Paul Jobling
Ksieve, sieving program developed by Phil Carmody
Srsieve, sieving program developed by Geoff Reynolds
LLR, primality program developed by Jean Penné
OpenPFGW, a primality program developed by Chris Nash & Jim Fougeron withmaintenance and improvements by Mark Rodenkirch

Entry in "The Largest Known Primes Database" can be found here:
https://primes.utm.edu/primes/page.php?id=122473
OpenPFGW, a primality program developed by Chris Nash & Jim Fougeron, was used to checkfor Fermat Number divisibility (including generalized and extended). For more information about
Fermat and generalized Fermat Number divisors, please see Wilfrid Keller's sites:• http://www.prothsearch.net/fermat.html• http://www.prothsearch.net/GFNfacs.html
Testing for Fermat, GFN, and xGFN divisors is still underway, and if any are found they will beannounced once that testing is complete.

PrimeGrid’s
Seventeen or Bust Subproject
The Seventeen or Bust Project was administered by Louis Helm, David Norris and MichaelGarrison.
Using a single PC would have taken centuries to find this prime. So this timely discovery would
not have been possible without the thousands of volunteers who contributed their spare CPUcycles. A special thanks to everyone who contributed their advice and/or computing power tothe search - especially all the sievers who work behind the scenes to make a find like thispossible.
PrimeGrid’s Seventeen or Bust subproject will continue to seek to eliminate the remaining 5 kvalues in the Sierpinski problem. To join the search please visit PrimeGrid:
http://www.primegrid.com.
For more information about Seventeen or Bust and the Sierpinski problem, please visit
http://primes.utm.edu/glossary/xpage/SierpinskiNumber.html.
About PrimeGrid
PrimeGrid is a distributed computing project, developed by Rytis Slatkevičius and currently
administered by Iain Bethune, James Breslin, Scott Brown, Ulrich Fries, Charley Gielkens,Michael Goetz, 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. Currently
BOINC is being developed by a 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
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 onhelper 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

PrimeGrid’s
Seventeen or Bust Subproject
For more information about PrimeGrid and a complete list of available prime search projects,
please visit: http://www.primegrid.com