Thread: GIMPS factors View Single Post 2014-09-05, 04:33 #3 ATH Einyen   Dec 2003 Denmark 2·1,571 Posts That is true and I have actually checked the numbers of factors with different k's. First there is no new examples where k=c*p, so the factor is 2*c*p^2 + 1, still only the one example: p=93077, c=674487. Here is a list of numbers of factors of each k-value up to k=1024, and a graph of some of the values: mersennefactors1.txt mersennefactors1.png For k=2 (mod 4) there is no factors since for those k-values 2kp+1 is not +/- 1 (mod 8) for any prime p. The number of factors goes down with higher k, but for each k=12*n there seems to be a local peak. The lowest number of factors seems to be at the prime k-values. Here is a list of all the factors ordered by the length of k in binary, so that is factors where 2n-1 <= k < 2n: (note that n=1 is just k=1, n=2: k=3, n=3: k=4,5,7) mersennefactors2.txt All the missing n-values have 0 factors of that length. Last fiddled with by ATH on 2014-09-05 at 04:40  