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A228869 Numbers n such that 2 * (1^n + 2^n + 3^n + ... + n^n) == 0 (mod n). 3
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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

MATHEMATICA

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

CROSSREFS

Cf. A228870, A226872.

Sequence in context: A031943 A023800 A320340 * A088725 A094520 A136447

Adjacent sequences:  A228866 A228867 A228868 * A228870 A228871 A228872

KEYWORD

nonn

AUTHOR

T. D. Noe, Sep 06 2013

STATUS

approved

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Last modified May 7 14:09 EDT 2021. Contains 343650 sequences. (Running on oeis4.)