OFFSET
1,3
COMMENTS
The primes where a(n) == 1 are given by A260507.
LINKS
Felix Fröhlich, Table of n, a(n) for n = 1..10000
MATHEMATICA
f[n_] := Block[{p = Prime@ n}, PowerMod[2^p + 1, p - 1, p^2]]; Array[f, 46] (* Robert G. Wilson v, Jul 29 2015 *)
PROG
(PARI) a(n) = lift(Mod(2^prime(n)+1, prime(n)^2)^(prime(n)-1))
CROSSREFS
KEYWORD
nonn
AUTHOR
Felix Fröhlich, Jul 28 2015
STATUS
approved