A015891 Numbers k such that k | 5^k + 5.

1, 2, 5, 6, 10, 30, 70, 1565, 2806, 3126, 51670, 58290, 214405, 285286, 378258, 1854766, 2170486, 2222122, 2247610, 3463230, 4147522, 5942526, 9381126, 14818486, 15743890, 20162858, 34087054, 34838686, 38742166, 71067430

Offset: 1

Author

Robert G. Wilson v

Keywords

• nonn

Links

• Giovanni Resta, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A067946 = numbers n such that n divides 5^n-1. Cf. A015951 = numbers n such that n | 5^n + 1.

Cf. A006517, A015888, A015889, A015892, A015893, A015897, A015898, A015902, A015903, A015904, A015905, A015906.

Programs

Mathematica

Select[Range[1000000], IntegerQ[(PowerMod[5,#,# ]+5)/# ]&] (* Alexander Adamchuk *)

Extensions

Corrected by Alexander Adamchuk, Nov 04 2006