OFFSET
1,1
COMMENTS
A double Mersenne number is a Mersenne number of the form 2^(2^p - 1) - 1, where p is a Mersenne exponent (A000043).
LINKS
Double Mersennes Prime Search, History
Wikipedia, Double Mersenne number
PROG
(PARI) forprime(p=2, , q=2^p-1; !ispseudoprime(q) && next(); if(ispseudoprime(2^q-1), print1(2^q-1, ", "); next()); forstep(r=2*q+1, +oo, 2*q, !ispseudoprime(r) && next(); if(Mod(2, r)^q-1 == 0, print1(r, ", "); next(2)))) \\ Jeppe Stig Nielsen, Aug 28 2019
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Arkadiusz Wesolowski, Oct 23 2015
STATUS
approved