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 26 September 2018, 13:24:01 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
5828034262144+1
The prime is 1,773,542 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 9 th for Generalized Fermat primes and 66 th overall.
The discovery was made by Rob Gahan ( Robish) of Ireland
using an NVIDIA GeForce GTX Titan X in an Intel(R) Core(TM) i7-5930K CPU at 3.50GHz with 32GB RAM, running Windows 10 Core Edition.
This GPU took about 2 hours and 36 minutes to probable prime (PRP) test with GeneferOCL3.
Rob is a member of the Storm team.
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 5 hours and 57 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
On 15 August 2018, 03:15:13 UTC, PrimeGrid's Sierpinski/Riesel Base 5 Problem project (SR5) eliminated k=194368 by finding the base 5 mega prime:
194368·52638045-1
The prime is 1,843,920 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 1 st for base 5 primes and 60 th overall.
69 k's now remain in the Riesel Base 5 Problem.
The discovery was made by Honza Cholt ( Honza) of the Czech Republic
using an Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz with 20 GB RAM running Microsoft Windows Server 2016.
This computer took about 4 hours and 44 minutes to complete the primality test using multithreaded LLR.
Honza is a member of the Czech National Team.
For more information, please see the Official Announcement.
On 4 August 2018, 09:10:53 UTC, PrimeGrid's Generalized Fermat Prime Search found the Generalized Fermat mega prime:
2312092524288+1
The prime is 3,336,572 digits long and enters Chris Caldwell's The Largest Known Primes Database
ranked 2 nd for Generalized Fermat primes and 24 th overall.
The discovery was made by Rob Gahan ( Robish) of Ireland
using an NVIDIA GeForce GTX 690 in an Intel(R) Core(TM) i7-3930K CPU at 3.20GHz with 12GB RAM, running Windows 10 Professional Edition.
This GPU took about 2 hours and 36 minutes to probable prime (PRP) test with GeneferOCL5.
Rob is a member of the Storm team.
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 20 hours and 55 minutes to complete the primality test using multithreaded LLR.
For more information, please see the Official Announcement.
Other significant primes
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News 
Restricted access to statistics files
Beginning October 12th, one week from today, access to the statistics files exported by PrimeGrid will be restricted to authorised statistics sites and other authorised users.
We're still working on the final plan, but if you are currently using our statistics files, please contact me either on the forums, by private message, or at the email address listed on our contacts page.
Michael Goetz
5 Oct 2018 | 16:02:22 UTC
· Comment
GFN-262144 Mega Prime!
On 26 September 2018, 13:24:01 UTC, PrimeGrid’s Generalized Fermat Prime Search found the Generalized Fermat mega prime:
5828034^262144+1
The prime is 1,773,542 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 9th for Generalized Fermat primes and 66th overall.
The discovery was made by Rob Gahan (Robish) of Ireland using an NVIDIA GeForce GTX Titan X in an Intel(R) Core(TM) i7-5930K CPU at 3.50GHz with 32GB RAM, running Windows 10 Core Edition. This GPU took about 25 minutes to probable prime (PRP) test with GeneferOCL3. Rob is a member of the Storm team.
The prime was verified on 26 September 2018, 13:51:13 by Jan Kumšta (Honza1616) of the Czech Republic using an NVIDIA GeForce GTX 1080 GPU in an AMD Ryzen 7 1700 CPU with 32GB RAM, running Windows 10 Professional Edition. This GPU took about 18 minutes to probable prime (PRP) test with GeneferOCL3. Jan is a member of the Czech National Team.
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 5 hours 57 minutes to complete the primality test using LLR.
For more details, please see the official announcement.
1 Oct 2018 | 10:50:56 UTC
· Comment
Genefer 3.3.4 now live
The latest release of genefer (3.3.4) is now released on BOINC labelled as app version 3.20. The client will download the new app automatically, no action is required on your part unless you are using app_info.xml (if you don't know what this means, don't worry).
The new version provides a speed-up of around 10% for AVX and FMA3 transforms for n=21, as well as providing support for multithreading. To enable it, create an app_config.xml file in your BOINC/projects/www.primegrid.com directory containing (for 2 threads per task)
<app_config>
<app_version>
<app_name>genefer</app_name>
<cmdline>-nt 2</cmdline>
<avg_ncpus>2</avg_ncpus>
<plan_class>cpuGFN21</plan_class>
</app_version>
</app_config>
Any problems or questions, let us know! Please note that as the new release does not affect the OCL code, the GPU app versions remain unchanged.
28 Sep 2018 | 8:02:29 UTC
· Comment
New SR5 Mega Prime!
On 15 August 2018, 03:15:13 UTC, PrimeGrid’s Sierpinski/Riesel Base 5 Problem project eliminated k=194368 by finding the mega prime:
194368*5^2638045-1
The prime is 1,843,920 digits long and will enter Chris Caldwell's The Largest Known Primes Database ranked 60th overall and is the largest known base 5 prime. 69 k's now remain in the Riesel Base 5 Problem.
The discovery was made by Honza Cholt (Honza) of the Czech Republic using an Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz with 20 GB RAM running Microsoft Windows Server 2016. This computer took about 4 hours 44 minutes to complete the primality test using multithreaded LLR. Honza is a member of the Czech National Team.
The prime was verified on 17 August 2018, 10:15:20 UTC by Deano Montreuil (Deano Montreuil) of the United States using an Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz with 8 GB RAM running Microsoft Windows 10 Core Edition. This computer took about 61 hours 55 minutes to complete the primality test using LLR. Deano is a member of the Aggie The Pew team.
For more details, please see the official announcement.
22 Aug 2018 | 13:51:16 UTC
· Comment
GFN-524288 Mega Prime!
On 4 August 2018, 09:10:53 UTC, PrimeGrid’s Generalized Fermat Prime Search found the Generalized Fermat mega prime:
2312092^524288+1
The prime is 3,336,572 digits long and enters Chris Caldwell's The Largest Known Primes Database ranked 2nd for Generalized Fermat primes and 24th overall.
The discovery was made by Rob Gahan (Robish) of Ireland using an NVIDIA GeForce GTX 690 in an Intel(R) Core(TM) i7-3930K CPU at 3.20GHz with 12GB RAM, running Windows 10 Professional Edition. This GPU took about 2 hours 36 minutes to probable prime (PRP) test with GeneferOCL5. Rob is a member of the Storm team.
The prime was verified on 4 August 2018, 23:28:14 UTC by Naoaki Tokuda (semanterion) of Japan using an NVIDIA Titan V in an Intel(R) Core(TM) i7-4960X CPU @ 3.60GHz with 64GB RAM, running Windows 7 Ultimate Edition. This GPU took about 24 minutes to probable prime (PRP) test with GeneferOCL5.
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 20 hours 55 minutes to complete the primality test using LLR.
For more details, please see the official announcement.
11 Aug 2018 | 13:08:34 UTC
· Comment
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News is available as an RSS feed 
Newly reported primes(Mega-primes are in bold.)
102975702^32768+1 (Kellen); 102847564^32768+1 (Kellen); 2215*2^1503176+1 (CGB); 102759712^32768+1 (Kellen); 9809*2^1503059+1 (dyost); 4122787074087*2^1290000-1 (TimT); 4122741442185*2^1290000-1 (Van Zimmerman); 54032538^131072+1 (DeleteNull); 7499*2^1502943+1 (Damian); 102464942^32768+1 (Fire$torm [BlackOps]); 102484816^32768+1 (Skligmund); 42757860^65536+1 (recoil44); 42743760^65536+1 (vaughan); 102299438^32768+1 (SEARCHER); 1595*2^1502647+1 (Kai Ylijoki); 7403*2^1502685+1 (CelticNinja); 4114727355567*2^1290000-1 (TimT); 102094462^32768+1 (Kellen); 2393*2^1502621+1 (Charles Jackson); 6981*2^1502616+1 (matzetoni) 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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