Double Mersenne number (source code)

= Double Mersenne number
{wiki=Double_Mersenne_number}

A Double Mersenne number is a special class of numbers that is defined using Mersenne numbers. Mersenne numbers are of the form \\( M_n = 2^n - 1 \\), where \\( n \\) is a positive integer. A Double Mersenne number is then defined as a Mersenne number whose index \\( n \\) itself is a Mersenne prime.