A015971 k is the first integer such that phi(k + n) | sigma(k).

1, 1, 3, 3, 5, 3, 6, 3, 6, 3, 11, 15, 6, 5, 14, 6, 14, 7, 24, 21, 6, 14, 6, 7, 15, 11, 24, 15, 10, 20, 6, 11, 22, 23, 45, 22, 6, 15, 14, 21, 30, 15, 14, 21, 10, 33, 12, 19, 27, 23, 62, 33, 22, 24, 22, 15, 14, 15, 14, 21, 26, 23, 42, 15, 14, 30, 20, 23, 46, 15, 14, 31, 26

Offset

0,3

Links

Table of n, a(n) for n=0..72.

Mathematica

Table[k = 1; While[! Divisible[DivisorSigma[1, k], EulerPhi[k + n]], k++]; k, {n, 0, 72}] (* Jayanta Basu, Jul 25 2013 *)

Crossrefs

Sequence in context: A033558 A046217 A057662 * A163167 A243729 A200810

Adjacent sequences: A015968 A015969 A015970 * A015972 A015973 A015974

Keyword

nonn

Author

Robert G. Wilson v

Status

approved