Cool Numbers The site analyzes 8-digit numbers for certain patterns including primes. The site will soon handle numbers of fewer and more digits. It is also developing a Cool Numbers index to give an absolute scale for patterns. Inquiries and suggestions are welcome through the site or to feedback@coolnumbers.com. I am currently looking for algorithms to search for specific patterns, whether prime-related or otherwise. http://www.coolnumbers.com
Factorization of numbers near googolplex Known prime factors of numbers in the range 10^(10^100) - 999 to 10^(10^100) + 999, including more than 57000 prime factors of googolplex + 10 and more than 34000 prime factors of googolplex - 10. http://www.alpertron.com.ar/GOOGOL.HTM
GMP GMP is a free library for arbitrary precision arithmetic, operating on signed integers, rational numbers, and floating point numbers. It is also assembly optimized for many processors. http://www.swox.com/gmp/
Generalized Fermat Prime Search The Generalized Fermat Prime (GFN) Search site, which allows you to submit ranges to search for GFN's. http://perso.wanadoo.fr/yves.gallot/primes/index.html
Nick's Mathematical Puzzles A variety of puzzles, with hints, answers, fully worked solutions, and links to related mathematical topics. New puzzles are added on a regular basis. http://www.qbyte.org/puzzles/
The Top-20 Prime Gaps The largest known prime gaps measured by absolute or relative size, or a combination http://users.cybercity.dk/~dsl522332/math/primegaps/gaps20.htm
