OFFSET
1,1
COMMENTS
Mersenne numbers (with the exception of the first two) are congruent to 31, 127, 271, 607 mod 6!. This sequence is a subsequence of A000043.
MATHEMATICA
Select[MersennePrimeExponent[Range[47]], PowerMod[2, #, 6!] == 272 &] (* Amiram Eldar, Mar 22 2020 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Artur Jasinski, Sep 30 2008
EXTENSIONS
a(10) from Amiram Eldar, Mar 22 2020
STATUS
approved