About
PrimeGrid's primary goal is to bring the excitement of prime finding to the "everyday" computer user. By simply
downloading and installing BOINC and attaching to the PrimeGrid project,
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 and enter into Chris Caldwell's The Largest Known Primes Database as
a Titan!
PrimeGrid's secondary goal is to provide relevant educational materials about primes. Additionally, we wish to contribute to the
field of mathematics.
Lastly, primes play a central role in the cryptographic systems which are used for computer security. Through the study of prime
numbers it can be shown how much processing is required to crack an encryption code and thus to determine whether current
security schemes are sufficiently secure. PrimeGrid is currently running several sub-projects:
- 321 Prime Search: searching for
mega primes of the form 3·2n±1.
- Cullen-Woodall Search: searching for
mega primes of forms n·2n+1 and
n·2n−1.
- Extended Sierpinski Problem: helping solve the Extended Sierpinski Problem.
- Generalized Fermat Prime Search: searching for
megaprimes of the form b2n+1.
- Prime Sierpinski Project: helping Prime Sierpinski Project solve the Prime Sierpinski Problem.
- Proth Prime Search: searching for primes of the form k·2n+1.
- Seventeen or Bust: helping to solve the Sierpinski Problem.
- Sierpinski/Riesel Base 5: helping to solve the Sierpinski/Riesel Base 5 Problem.
- Sophie Germain Prime Search: searching for primes p and 2p+1.
- The Riesel problem: helping to solve the Riesel Problem.
Recent Significant Primes
On 12 November 2016, 17:02:17 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
673·23330436+1
The prime is 1,002,564 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 193 rd overall.
The discovery was made by Randall Scalise ( Randall J. Scalise) of the United States
using an Intel(R) Core(TM) i5-4590 CPU @ 3.50GHz with 8GB RAM, running Linux. This computer took about 1 hour 12 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
On 31 October 2016, 22:13:54 UTC, PrimeGrid's Seventeen or Bust subproject found the mega prime:
10223·231172165+1
The prime is 9,383,761 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 7 th 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, 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.
The discovery was made by Szabolcs Peter ( Syp) of Hungary
using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 12GB RAM, running Windows 10 Enterprise Edition.
This computer took about 8 days, 22 hours and 34 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
On 4 November 2016, 06:03:37 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
655·23327518+1
The prime is 1,001,686 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 196 th overall.
The discovery was made by Paul Mazumdar ( pm107) of the United Kingdom
using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 16GB RAM, running Windows 10 Education Edition. This computer took about 1 hour and 5 minutea to complete the primality test using LLR.
Paul is a member of the University of Cambridge team.
For more information, please see the Official Announcement.
On 3 November 2016, 17:52:13 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
659·23327371+1
The prime is 1,001,642 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 196 th overall.
The discovery was made by Dejana Ristic ( Dejana Ristic) of Germany
using an Intel(R) Xeon(R) CPU E3-1245 v3 @ 3.40GHz with 8GB RAM, running Windows 7 Enterprise Edition. This computer took about 1 hour and 1 minute to complete the primality test using LLR.
Dejana is a member of the Rechenkraft.net team.
For more information, please see the Official Announcement.
On 3 November 2016, 23:35:42 UTC, PrimeGrid's AP27 Search project (Arithmetic Progression of 27 primes) found the progression of 26 primes:
149836681069944461+7725290*23#*n for n=0..25
The discovery was made by Takeshi Nakamura ( kurogane-t) of Japan
using an NVIDIA GTX 1070 on an Intel(R) Xeon(R) E5-2667 v3 @ 3.20GHz with 16GB RAM, running Windows 10 Core x64 Edition.
This computer took about 30 minutes to process the task (each task tests 100 progression differences of 10 shifts each).
Takeshi is a member of the BOINC@MIXI team.
For more information, please see the Official Announcement.
On 2 November 2016, 16:08:03 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
821·23327003+1
The prime is 1,001,531 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 196 th overall.
The discovery was made by Randall Scalise ( Randall J. Scalise) of the United States
using an Intel(R) Core(TM) i5-4590 CPU @ 3.50GHz with 8GB RAM, running Linux. This computer took about 1 hour and 1 minute to complete the primality test using LLR.
For more information, please see the Official Announcement.
On 30 October 2016, 07:20:52 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
555·23325925+1
The prime is 1,001,206 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 196 th overall.
The discovery was made by Alexander Falk ( Alexander Falk) of the United States
using an Intel(R) Core(TM) i7-4690HQ CPU @ 2.60GHz with 16GB RAM, running Windows 10 Professional. This computer took about 4 hours 12 minutes to complete the primality test using LLR.
Alexander is a member of the The Knights Who Say Ni! team.
For more information, please see the Official Announcement.
On 24 October 2016, 17:17:12 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
791·23323995+1
The prime is 1,000,626 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 197 th overall.
The discovery was made by Randall Scalise ( Randall J. Scalise) of the United States
using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM, running Linux. This computer took about 1 hour 8 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
On 21 October 2016, 18:12:50 UTC, PrimeGrid's PPS Mega Prime Search project found the mega prime:
597·23322871+1
The prime is 1,000,287 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 197 th overall.
The discovery was made by Randall Scalise ( Randall J. Scalise) of the United States
using an Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz with 8GB RAM, running Linux. This computer took about 1 hour 11 minutes to complete the primality test using LLR.
For more information, please see the Official Announcement.
Other significant primes
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News 
Wallis is Born Challenge Starts November 18th at 18:00 UTC
Please join us for the Wallis is Born Challenge, running for 5 days from November 18th 18:00:00 UTC until November 23rd 18:00:00 UTC. This challenge is running the AP27 app only.
For more information, please see the official challenge thread: http://www.primegrid.com/forum_thread.php?id=7084
15 Nov 2016 | 22:56:21 UTC
· Comment
Another PPS Mega Prime!
On 12 November 2016, 17:02:17 UTC, PrimeGrid’s PPS Mega Prime Search project found the Mega Prime:
673*2^3330436+1
The prime is 1,002,564 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 193rd overall.
The discovery was made by Randall Scalise (Randall J. Scalise) of the United States using an Intel(R) Core(TM) i5-4590 CPU @ 3.50GHz with 8GB RAM, running Linux. This computer took about 1 hour 12 minutes to complete the primality test using LLR.
The prime was verified on 12 November 2016, 17:23:33 UTC by John S. Chambers (Johnny Rotten) of the United States using an Intel(R) Core(TM) i7-3770K CPU @ 3.50GHz with 16GB RAM, running Microsoft Windows 7 Professional Edition. This computer took about 1 hour 23 minutes to complete the primality test using LLR. John is a member of the SETI.USA team.
For more details, please see the official announcement.
14 Nov 2016 | 12:56:38 UTC
· Comment
World Record Colbert Number discovered!
On 31 October 2016, 22:13:54 UTC, PrimeGrid’s Seventeen or Bust subproject found the Mega Prime:
10223*2^31172165+1
The prime is 9,383,761 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 7th 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, 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 a collaboration between PrimeGrid and Seventeen or Bust. This discovery would not have been possible without all the work done over the years by Seventeen or Bust.
The discovery was made by Szabolcs Peter (SyP) of Hungary using an Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz with 12GB RAM, running Windows 10 Enterprise Edition. This computer took about 8 days, 22 hours, 34 minutes to complete the primality test using LLR.
Information regarding double checking will be announced at a later date.
For more details, please see the official announcement.
9 Nov 2016 | 16:57:51 UTC
· Comment
Yes, its another PPS Mega Prime!
On 4 November 2016, 06:03:37 UTC, PrimeGrid’s PPS Mega Prime Search project found the Mega Prime:
655*2^3327518+1
The prime is 1,001,686 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 196th overall.
The discovery was made by Paul Mazumdar (pm107) of the United Kingdom using an Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz with 16GB RAM, running Windows 10 Education Edition. This computer took about 1 hour 5 minutes to complete the primality test using LLR. Paul is a member of the University of Cambridge team.
The prime was verified on 4 November 2016, 14:34:01 UTC by Toshitaka Kumagai (Toshitaka Kumagai) of Japan using an Intel(R) Xeon(R) CPU E5-2643 @ 3.30GHz with 256GB RAM, running Windows 10 Core Edition. This computer took about 1 hour 22 Minutes to complete the primality test using LLR.
For more details, please see the official announcement.
5 Nov 2016 | 11:32:12 UTC
· Comment
Another PPS Mega Prime!
On 3 November 2016, 17:52:13 UTC, PrimeGrid’s PPS Mega Prime Search project found the Mega Prime:
659*2^3327371+1
The prime is 1,001,642 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 196th overall.
The discovery was made by Dejana Ristic (Dejana Ristic) of Germany using an Intel(R) Xeon(R) CPU E3-1245 v3 @ 3.40GHz with 8GB RAM, running Windows 7 Enterprise Edition. This computer took about 1 hour 1 minute to complete the primality test using LLR. Dejana is a member of the Rechenkraft.net team.
The prime was verified on 4 November 2016, 09:03:57 UTC by Steve King (steveking) of the United States using an Intel(R) Core(TM) i3-4010U CPU @ 1.70GHz with 12GB RAM, running Windows 10 Core Edition. This computer took about 4 hours to complete the primality test using LLR.
For more details, please see the official announcement.
5 Nov 2016 | 10:53:25 UTC
· Comment
... more
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Newly reported primes3155621049735*2^1290000-1 (Randall J. Scalise); 38794556^32768+1 (Soulfly); 3153599285835*2^1290000-1 (Randall J. Scalise); 8325*2^1426153+1 (Stefan); 3153161314935*2^1290000-1 (aolder); 3152361811965*2^1290000-1 (Randall J. Scalise); 38732164^32768+1 (sangis43); 3153766353855*2^1290000-1 (Randall J. Scalise); 9287*2^1426099+1 (KD7LRJ); 38672504^32768+1 (Soulfly); 2219*2^1426071+1 (Randall J. Scalise); 38572858^32768+1 (Soulfly); 15948188^65536+1 (Krzysiak_PL_GDA); 38532442^32768+1 (Sysadm@Nbg); 3150288030417*2^1290000-1 (Randall J. Scalise); 3148486309197*2^1290000-1 (post-factum); 15893070^65536+1 (288larsson); 3144778890027*2^1290000-1 (ETX); 38437674^32768+1 (teppot); 3147765440787*2^1290000-1 (Teuvo Korhonen) Last 24 hoursTop participants by work done in the last 24 hours | Top teams by work done in the last 24 hours |
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