OFFSET
1,2
COMMENTS
sigma_9(n) is the sum of the 9th powers of the divisors of n (A013957).
MATHEMATICA
Do[If[Mod[DivisorSigma[9, n]-EulerPhi[n]^9, n]==0, Print[n]], {n, 1, 10^5}]
PROG
(PARI) isok(n) = !((sigma(n, 9) - eulerphi(n)^9) % n); \\ Michel Marcus, Mar 02 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Jun 09 2000
EXTENSIONS
Definition corrected by Michel Marcus, Mar 02 2014
STATUS
approved