About
PrimeGrid's primary goal is to advance mathematics by enabling everyday computer users to contribute their system's processing power towards prime finding. 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 17 April 2019, 11:00:27 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
2788032524288+1
The prime is 3,379,193 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 3 rd for Generalized Fermat primes and 26 th overall.
The discovery was made by Ed Goforth ( BlisteringSheep) of the Netherlands Antilles
using an NVIDIA GeForce GTX 760 in an Intel(R) Xeon(R) CPU E5-2687W v3 @ 3.10GHz with 128GB RAM, running Linux.
This GPU took about 3 hours and 30 minutes to probable prime (PRP) test with GeneferOCL5.
Ed is a member of the Christians team.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 15GB RAM, running Microsoft Windows 10 Professional x64 Edition.
This computer took about 25 hours and 3 minutes to complete the primality test using multithreaded LLR.
On 18 March 2019, 07:26:42 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
2733014524288+1
The prime is 3,374,655 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 3 rd for Generalized Fermat primes and 26 th overall.
The discovery was made by Yair Givoni ( Yair Givoni) of Israel
using an NVIDIA GeForce GTX 960 in an Intel(R) Core(TM) i5-6600 CPU @ 3.30GHz with 16GB RAM, running Windows 10 Core x64 Edition.
This GPU took about 2 hours and 57 minutes to probable prime (PRP) test with GeneferOCL3.
Yair is a member of The Planetary Society team.
The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 4GB RAM, running Linux Debian.
This computer took about 26 hours and 43 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
On 14 December 2018, 07:07:34 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
6291332262144+1
The prime is 1,782,250 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 10 th for Generalized Fermat primes and 66 th overall.
The discovery was made by Karsten Freihube ( KFR) of Germany
using an NVIDIA GeForce GTX 1060 in an Intel(R) Core(TM) i7-4790 CPU at 3.60GHz with 16GB RAM, running Windows 10 Proffesional Edition.
This GPU took about 35 minutes to probable prime (PRP) test with GeneferOCL2.
The PRP was confirmed prime by an Intel(R) Core(TM) i7-7700K CPU @ 4.20GHz with 16GB RAM, running Microsoft Windows 10 Professional.
This computer took about 4 hours and 59 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
Other significant primes
2788032524288+1 (GFN):
official announcement pending | Generalized Fermat Prime
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News 
GFN-17-MEGA Is Now GPU-ONLY
Effective immediately, CPU tasks for GFN-17-MEGA have been disabled. This project is now GPU-only.
The B-limit for the CPU x87 transform has been reached, and from this point on more and more GFN-17-MEGA tasks would fail on CPUs.
Only GFN-17-MEGA is affected. All of our other projects will continue operating as usual.
More discussion can be found here: https://www.primegrid.com/forum_thread.php?id=8558.
22 Apr 2019 | 13:40:56 UTC
· Comment
GFN-524288 Mega Prime!
On 18 March 2019, 07:26:42 UTC, PrimeGrid’s Generalized Fermat Prime Search found the Generalized Fermat mega prime:
2733014^524288+1
The prime is 3,374,655 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 3rd for Generalized Fermat primes and 26th overall.
The discovery was made by Yair Givoni of Israel using an NVIDIA GeForce GTX 960 in an Intel(R) Core(TM) i5-6600 CPU @ 3.30GHz CPU with 16GB RAM, running Windows 10. This GPU took about 2 hours 57 minutes to probable prime (PRP) test with GeneferOCL3. Yair is a member of The Planetary Society team.
The PRP was confirmed prime by an Intel(R) Xeon(R) CPU E3-1240 v6 @ 3.70GHz with 4GB RAM, running Linux Debian. This computer took about 26 hours and 43 minutes to complete the primality test using multithreaded LLR.
For more details, please see the official announcement.
10 Apr 2019 | 0:28:50 UTC
· Comment
GCW Sieve is shutting down May 1st
This is the official 30 day warning.
On May 1st we will turn off the work generator for the GCW Sieve project. We expect all bases to have reached optimal sieving depth by then.
If you need extra credit for a badge or hours for WUProp, now is the time to get it.
For more information and discussion, please see this forum thread.
28 Mar 2019 | 20:40:06 UTC
· Comment
Forum threads locked after a year
Effective immediately, forum threads will be automatically locked one year after the most recent post. If a thread has been inactive for a year, it's better to start a new thread than to reactivate a moribund thread.
If you need to reference something in the old thread, you can always link to the original post or thread using the [url]http://www.primegrid.com/something...[/url] tag.
23 Feb 2019 | 18:06:29 UTC
· Comment
PrimeGrid and BOINC are looking for experienced Macintosh Developers
PrimeGrid is currently looking for a volunteer developer to build, test and maintain Mac apps. The current developer of PrimeGrid (and other applications that are used in the mathematics/prime search world) is no longer able to help us maintain the applications, which means that we may need to drop support for Macs over time (no such changes are planned right now or in the immediate future).
If you are able to help us, please don't hesitate to get in touch.
Moreover, the Berkeley Open Infrastructure for Network Computing (BOINC) open source project, which is the software infrastructure used by PrimeGrid and many other volunteer distributed computing projects, is also looking for volunteers to develop and maintain the BOINC client on Macintosh. The BOINC Client and Manager are C++ cross-platform code supporting MS Windows, Mac, Linux, and several other operating systems. BOINC currently has a number of volunteer developers supporting Windows and Linux, but their main Mac developer is winding down his involvement after many years. He is prepared to help a few new Mac developers get up to speed.
If you have Mac development experience and are interested in volunteering time to help support and maintain the BOINC Mac client please have a look at the more detailed description here: https://boinc.berkeley.edu/trac/wiki/MacDeveloper
If you are not a Mac developer, but have other skills and are interested in contributing to BOINC, the link above also has more general information.
19 Feb 2019 | 11:35:16 UTC
· Comment
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Newly reported primes(Mega-primes are in bold.)
4399806688545*2^1290000-1 (recoil44); 4400914701297*2^1290000-1 (x3mEn); 121730360^32768+1 (JH30895); 61135724^65536+1 (288larsson); 4673*2^1536693+1 (dthonon); 4400021673045*2^1290000-1 (TimT); 121629290^32768+1 (y-mori); 4389208350147*2^1290000-1 (TheDawgz); 121605858^32768+1 (Kellen); 4397746797897*2^1290000-1 (DeleteNull); 4394696359167*2^1290000-1 (beijinghouse); 15091270^131072+1 (k4m1k4z3); 4395871827795*2^1290000-1 (MAGPIE); 121404522^32768+1 (Kellen); 121394090^32768+1 (mikey); 121395346^32768+1 (Kellen); 121347184^32768+1 (GregCinAZ); 4391869896615*2^1290000-1 (beijinghouse); 4391682705795*2^1290000-1 (beijinghouse); 4381595441667*2^1290000-1 (Darryl) 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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