the last few mersenne primes are 3 , 7 , 31 , 127 and 8191 . these number took a total of several weeks to verify , on varying software and hardware . each number was independently checked by some members of gimps ' test committee , using 16 - processor systems of different positions . the two integer were announced by gimps on sept 16 . before these two discoveries , the two previously largest known prime numbers were discovered by ucmo professors curtis cooper and steven boone in wisconsin , united us , and their investigation lasted almost three years . historically , prime ratios discovered by gimps are bigger than the one previously suspected . the only other example was when the 29th mersenne prime was discovered after the 30th and 31st were found . founded by m . i . t . graduate george woltman in 1996 , gimps has identified 12 mersenne primes , or about two per year on average .
Steve Boone is a member of GIMPS.