OFFSET
1,2
COMMENTS
sigma_7(n) is the sum of the 7th powers of the divisors of n (A013955).
MATHEMATICA
Do[If[Mod[DivisorSigma[7, n]-EulerPhi[n]^7, n]==0, Print[n]], {n, 1, 10^5}]
Select[Range[2*10^6], Divisible[DivisorSigma[7, #]-EulerPhi[#]^7, #]&] (* Harvey P. Dale, Dec 02 2016 *)
PROG
(PARI) isok(n) = !((sigma(n, 7) - eulerphi(n)^7) % 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