OFFSET
1,4
COMMENTS
a(n)=1 iff n is prime. Apparently a(n)>2 for composite n's.
MATHEMATICA
Table[Mod[DivisorSigma[1, n^2], DivisorSigma[1, n]], {n, 200000}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Mar 06 2011
STATUS
approved