Factoring

From SeventeenOrBust

Factoring is called the attempt to find quickly (in several hours) a factor for a particular k,n-pair, proving that it is composite and thus not prime, and saving so PRP-tests, which take up to several weeks, depending on the processor speed.

The software used is George Woltman's prime95, which searches for P-1-smooth factors, i.e. factors p for which p − 1 has relatively small factors.

See also the P-1 bound optimisation page.