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15k Search

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The 15k Search is a project based on two main goals:

The first goal is, to spend as little CPU time as possible, per titanic prime found.

In order to do this we use the fastest programs possible to return primes of special forms.
New forms may be found of interest as new theoretical applications are developed into reality.
15k was the first such form exploited by our group, for it's heavy candidate density.
The weight was obtained using Nash and Robinson weight softwares.
This was the initial phase, to gather information about heavy k, for later use with fixed n forms.
Fixed n searches are faster than fixed k, and can be used in conjunction with heavy 15k.

The second goal is, to find a prime in a secure manner, worthy of an E.F.F. prize.

Theory and practice

The "theory" of the project and it's client is, that by following the quidelines, written by Paul Jobling, novice users will be more likely to look for primes, and will find them quicker.

In the help contents of NewPGen it states the prime directive

"In general, you ought to sieve until the rate at which NewPGen is throwing out composites is equal to the rate at which Proth/PRP/PFGW can perform a primality test on the numbers. Actually, you should stop a little sooner - the idea is to find primes, after all."

The "practice" part is that, an automation client has been written for NewPGen, and LLR in Microsoft Visual Basic .NET. The client gives the 15k search a speed advantage over any other project not using the software. You can get more information about it here.

How to participate

Novice users should download RMA.NET and then simply click start.

Contact 15k with your intention to join, and candidate range.
After you've found a prime, send Chris Caldwell an email at,
and inform him that you need a new prover code.
Submit your prime number, and list all the programs you've used to find the prime.
Be sure to mention that you found it as a member of 15k.

Downloading the client

You will need Microsoft's .NET framework installed in order to run RMA.NET. You'll also need to download NewPGen and LLR.


This project is now on hold.


Over time, the 15k Search has for the most part, kept the overall lead in the The Prime Pages by number of primes found. With formidable new competition around, the stakes have been raised.

The 15k Search has not found any 10M+ digit primes yet, although 15k Search members had a plausible chance at finding one first.

As of June 2006, the 15k Search has been terminated.

External links