Over the years it has been found that Mersenne was wrong about 5 of the primes of the form 2p - 1 where p is less than or equal to 257 (he claimed two that didn't lead to a prime (67 and 257) and missed 3 that did: 61, 89, 107).
Sa paglipas ng taon na ito ay natagpuan na Mersenne ay mali tungkol sa 5 ng primes ng form 2 p - 1 p kung saan ay mas mababa kaysa sa o katumbas ng 257 (siya inaangkin ng dalawang na hindi humahantong sa isang kalakasan (67 at 257) at Naiwan 3 na ay: 61, 89, 107).