OFFSET
1,2
COMMENTS
sigma_11(n) is the sum of the 11th powers of the divisors of n (A013959).
MATHEMATICA
Do[If[Mod[DivisorSigma[11, n]-EulerPhi[n]^11, n]==0, Print[n]], {n, 10^5}]
Select[Range[800000], Divisible[DivisorSigma[11, #]-EulerPhi[#]^11, #]&] (* Harvey P. Dale, Apr 15 2018 *)
PROG
(PARI) isok(n) = !((sigma(n, 11) - eulerphi(n)^11) % n); \\ Michel Marcus, Mar 02 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Jun 09 2000
EXTENSIONS
Definition corrected and more terms from Michel Marcus, Mar 02 2014
STATUS
approved