A055697 Numbers k such that k | sigma_3(k) - phi(k)^3.

1, 2, 10, 12, 78, 198, 1278, 1470, 1491, 2376, 2472, 6768, 7659, 7774, 9858, 10912, 11904, 12862, 16660, 25758, 35586, 38976, 39102, 40986, 41144, 44688, 59520, 72961, 80304, 84084, 94365, 104328, 119070, 153370, 174966, 200970, 230040, 291696, 358680, 376404

Offset

1,2

Comments

sigma_3(k) is the sum of the cubes of the divisors of n (A001158).

Links

Amiram Eldar, Table of n, a(n) for n = 1..282 (terms below 10^10)

Mathematica

Do[If[Mod[DivisorSigma[3, n]-EulerPhi[n]^3, n]==0, Print[n]], {n, 1, 2*10^5}]

Crossrefs

Cf. A000010, A001158, A055970.

Sequence in context: A106455 A209445 A181427 * A055705 A156430 A347336

Adjacent sequences: A055694 A055695 A055696 * A055698 A055699 A055700

Keyword

nonn

Author

Robert G. Wilson v, Jun 09 2000

Extensions

More terms from Sean A. Irvine, Apr 03 2022

Status

approved