A020489 Numbers k such that phi(k) divides sigma_0(k).

1, 2, 3, 6, 8, 10, 18, 24, 30

Offset

1,2

Links

Table of n, a(n) for n=1..9.

Mathematica

Select[Range[30], Divisible[DivisorSigma[0, #], EulerPhi[#]] &] (* Amiram Eldar, May 15 2024 *)

Crossrefs

Cf. A000005 (sigma_0), A000010 (phi).

Sequence in context: A082667 A098162 A076627 * A002240 A099798 A230108

Adjacent sequences: A020486 A020487 A020488 * A020490 A020491 A020492

Keyword

nonn,fini,full

Author

David W. Wilson

Status

approved