A015808 k is the first integer such that phi(k) + n | sigma(k).

1, 6, 2, 12, 6, 4, 14, 9, 22, 26, 6, 8, 24, 20, 10, 45, 15, 58, 14, 117, 21, 74, 24, 16, 12, 52, 22, 169, 30, 40, 26, 68, 39, 18, 20, 289, 42, 3604, 34, 146, 51, 72, 38, 180, 28, 730, 48, 32, 70, 116, 46, 194, 24, 150, 45, 1632, 115, 104, 120, 226, 78, 80, 58

Offset

0,2

Links

Table of n, a(n) for n=0..62.

Mathematica

a[n_] := Module[{k = 1}, While[!Divisible[DivisorSigma[1, k], EulerPhi[k] + n], k++]; k]; Array[a, 30, 0] (* Amiram Eldar, Dec 10 2018 *)

Crossrefs

Cf. A015791.

Sequence in context: A065284 A050088 A163864 * A112591 A106034 A194036

Adjacent sequences: A015805 A015806 A015807 * A015809 A015810 A015811

Keyword

nonn

Author

Robert G. Wilson v

Extensions

a(1) corrected by Sean A. Irvine, Dec 10 2018

Status

approved