OFFSET
1,3
COMMENTS
Prime terms are 17, 37, 197, 2617, 5437, 65537, 437837, ...
Numbers t such that 2^t + 1 is a term are 4, 9, 12, 16, 21, 24, 36, 37, 40, 45, 49, 52, 57, 64, 69, 76, 84, 96, ...
MATHEMATICA
Select[Range[0, 9999], Divisible[2^# + 8, #^2 + 1] &] (* Alonso del Arte, Sep 16 2018 *)
PROG
(PARI) isok(n)=Mod(2, n^2+1)^n==-8;
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Altug Alkan, Sep 15 2018
EXTENSIONS
a(21)-a(24) from Hiroaki Yamanouchi, Sep 16 2018
STATUS
approved