OFFSET
1,2
COMMENTS
3 divides a(n) for n > 1. 7 divides a(n) for n > 2.
MATHEMATICA
Select[Range[5*10^6], Mod[ 5^(#^2)+1, #^3]==0 &] (* G. C. Greubel, Jan 18 2018 *)
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Alexander Adamchuk, Mar 31 2007
EXTENSIONS
More terms from Ryan Propper, Dec 31 2007
STATUS
approved