Quote:
Originally Posted by MatWurS530113
But the real problems are M3259 and M4729
from both numbers 1 factor is known at the GIMPSdatabase:
M3259: 21926805872270062496819221124452121
M4729: 61944189981415866671112479477273
my proggy says: the remaining cofactors of these Mnumbers are still composite.

According to Mathematica (PrimeQ) the cofactors are both prime.
Edgingtons factoredM.txt agrees, which indicates he has primality certificates.
I guess your program contains a bug...