A015893 Numbers k such that k | 7^k + 7.

1, 2, 4, 7, 8, 14, 28, 35, 56, 91, 172, 175, 616, 742, 904, 946, 1204, 1267, 1288, 2275, 2486, 4795, 5551, 7288, 10396, 10696, 16426, 16471, 18536, 31675, 34126, 38872, 40132, 40775, 58618, 61075, 67768, 72136, 78604, 86296, 117656

Offset: 1

Author

Robert G. Wilson v

Keywords

• nonn

Links

• Giovanni Resta, Table of n, a(n) for n = 1..1200

Crossrefs

Cf. A006517, A015888, A015889, A015891, A015892, A015897, A015898, A015902, A015903, A015904, A015905, A015906.

Programs

Mathematica

Select[Range[10^5], Mod[PowerMod[7, #, #] + 7, #] == 0 &] (* Giovanni Resta, Oct 23 2018 *)

Extensions

Missing a(2)-a(3) from Giovanni Resta, Oct 23 2018