A228869 Numbers n such that 2 * (1^n + 2^n + 3^n + ... + n^n) == 0 (mod n).

1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 22, 23, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 37, 38, 39, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 79, 81, 82, 83

Offset: 1

Author

T. D. Noe, Sep 06 2013

Keywords

• nonn

Comments

See A228870 for the numbers not in this sequence.

Union of A226872 and the positive odd integers (A005408).

Also, positive integers n such that (p-1) does not divide n for every odd prime p dividing n (cf. A124240). - Max Alekseyev, Sep 07 2013

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A228870, A226872.

Programs

Mathematica

Select[Range[100], Mod[2*Sum[PowerMod[k, #, #], {k, #}], #] == 0 &]