mersenneforum.org (Popularity: )
http://www.mersenneforum.org/ A forum about prime numbers and computerized searches for more of them. Includes discussions of software and hardware issues encountered ...
Number Spiral (Popularity: )
http://www.numberspiral.com/ Explains this method of visually representing the distribution of primes and the relationships between factors and products.
Primo (Popularity: )
http://www.ellipsa.net/ Elliptic Curve Primality Proving (ECPP) implementation. Freeware by Marcel Martin.
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