OFFSET
1,2
COMMENTS
Sigma_4(n) is the sum of the 4th powers of the divisors of n (A001159).
MATHEMATICA
Do[If[Mod[DivisorSigma[4, n] + EulerPhi[n]^4, n]==0, Print[n]], {n, 1, 10^6}]
PROG
(PARI) isok(k) = (sigma(k, 4) + eulerphi(k)^4)%k == 0; \\ Jinyuan Wang, Mar 17 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Jun 09 2000
EXTENSIONS
More terms from Robert G. Wilson v, Mar 11 2013
More terms from Jinyuan Wang, Mar 17 2020
STATUS
approved