Comment Re:"Not only" the largest Mersenne prime ... (Score 2, Informative) 296
I am not sure when a non-Mersenne last had that status, but it is a rare occurrence.
391581*2^216193-1 was the largest known prime from 1989 to 1992. Before that, the last non-Mersenne record was 1951-1952. A complete list can be found here.
391581*2^216193-1 was the largest known prime from 1989 to 1992. Before that, the last non-Mersenne record was 1951-1952. A complete list can be found here.
