Timing[PrimeQ[(32*10^6959 - 23)/99]] {198.245 Second, True} The above is from a Mathematica run. That's better than a 1.5 year run. I fairly certain that any of the major math programs is faster than Marcel Martin's Primo program. For what it's worth, (32*10^n - 23)/99 is composite from 6960 to 7500. --Ed Pegg Jr, www.mathpuzzle.com --- Richard Schroeppel <rcs@CS.Arizona.EDU> wrote:
I think this is a size record for verifying a prime with a generic method (that doesn't use any special form information about the number).
The number tested has 6959 digits (23116 bits). The test took 1.5 years. The first 25% of the elapsed time reduced the size of the number being checked by 8%. ........................ I would like to inform you that I have certified the primality of (32*10^6959-23)/99, a smoothly undulating palindromic prime (SUPP) [1] having 6959 decimal digits, with the program Primo [2], Marcel Martin's implementation of the elliptic curve primality proving (ECPP) algorithm.