A055698 Numbers n such that n | (sigma_4(n) + phi(n)^4).

1, 2, 6, 13588, 48238, 54490, 69004, 194460, 353228, 577980, 638652, 1478962, 1882188, 2190515, 2677740, 3404598, 3875508, 8456460, 9978863, 16320458, 41199780, 45112860, 76132715, 236405988, 357846865, 682983756, 689274612, 733141332, 1185444052, 1752193128

Offset: 1

Author

Robert G. Wilson v, Jun 09 2000

Keywords

• nonn

Comments

Sigma_4(n) is the sum of the 4th powers of the divisors of n (A001159).

Crossrefs

Cf. A001159.

Programs

Mathematica

Do[If[Mod[DivisorSigma[4, n] + EulerPhi[n]^4, n]==0, Print[n]], {n, 1, 10^6}]

PARI

isok(k) = (sigma(k, 4) + eulerphi(k)^4)%k == 0; \\ Jinyuan Wang, Mar 17 2020

Extensions

More terms from Robert G. Wilson v, Mar 11 2013

More terms from Jinyuan Wang, Mar 17 2020