Thread: Welcome!
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Old 2007-03-24, 15:44   #1
hhh
 
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Jun 2005

373 Posts
Default Welcome!

This project is searching a Cullen prime, i.e. a prime of the form n*2^n+1, with prime exponent.

The project consists of three parts:

Sieving with gcwsieve and the sieve.txt in the sieve reservation thread is going to be finished soon, but still available,

P-1 with prime95 or mprime can be reserved in the P-1 reservation thread and will advance as it becomes necessary, and

LLR, the actual prime hunting, with the LLR-client (not LLRnet); the content for the input files needs to be copy/pasted in the LLR-reservation thread.

Currently, there are about 4000 tests below 5M remaining, and any substantial help is appreciated to finish them off.

Background:There are 14 Cullen primes known, but only with composite exponents, and nobody knows if there is one with a prime exponent. That's why this project exists.

The first stage of the project is the search in the range n=1.5M-5M. Below 1.5M, all Cullen numbers have been tested by others and no prime exponent yielded a prime(Doublecheck up to 400000). The range we are working on for the moment has been sieved by the same people up to 2.5 G, and with the improvements done by Citrix to Mark Rodenkirchs multisieve, and geoff's gcwsieve, based on Rodenkirch's code as well, currently being sieved beyond 3000G.

This project, given its small scale, is mostly run manually; reservations, database, all this is not automated and will probably never be. So, please don't expect realtime handling of the results etc, but the organisation should take place in reasonable delys, normally.

Stats are not planned for the moment, but your reservations are going to be kept public in the reservation threads, so that one can figure out how much you contributed.

Finally, welcome again, and let us find that prime and finish the project soon.

Yours H.

Last fiddled with by hhh on 2007-05-05 at 07:32
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