OFFSET
1,1
COMMENTS
First 22 terms are obtained by Mathematica. Terms from 23 to 38 are obtained by Jean Penna's LLR program.
LINKS
EXAMPLE
First Mersenne number N(1)=2, 2^2-1=3 is the first Mersenne prime. 3*2^2-1=11 is prime;
Fifth Mersenne number N(5)=13, 2^13-1=8191 is the fifth Mersenne prime. 9*2^13-1=73727 is prime.
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Lei Zhou, Dec 13 2007
EXTENSIONS
a(35)-a(37) from Pierre CAMI, Apr 06 2015
a(38) from Lei Zhou, Sep 04 2022
STATUS
approved