A015774 Numbers k such that phi(k) | sigma_15(k).

1, 2, 3, 6, 12, 14, 15, 30, 35, 38, 42, 46, 54, 56, 70, 78, 87, 95, 105, 114, 126, 134, 135, 138, 140, 147, 161, 168, 174, 182, 184, 190, 209, 210, 215, 216, 222, 230, 248, 258, 264, 270, 285, 294, 297, 299, 315, 322, 357, 398, 402, 414, 418, 420

Offset

1,2

Comments

sigma_15(n) is the sum of the 15th powers of the divisors of n.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[420], Divisible[DivisorSigma[15, #], EulerPhi[#]] &] (* Amiram Eldar, Nov 02 2019 *)

Crossrefs

Cf. A000010, A013963.

Cf. A020492, A015759, A015761, A015762, A015763, A015764, A015765, A015766, A015767, A015768, A015769, A015770, A015771, A015773, A094470.

Sequence in context: A287109 A084417 A324243 * A015767 A015761 A015763

Adjacent sequences: A015771 A015772 A015773 * A015775 A015776 A015777

Keyword

nonn

Author

Robert G. Wilson v

Extensions

Offset corrected by Amiram Eldar, Nov 02 2019

Status

approved