A116621 - OEIS

A116621

Positive integers n such that 13^n == 1 (mod n).

1, 2, 3, 4, 6, 8, 9, 12, 14, 16, 18, 20, 24, 27, 28, 32, 36, 40, 42, 48, 54, 56, 60, 64, 68, 72, 80, 81, 84, 96, 98, 100, 108, 112, 120, 126, 128, 136, 140, 144, 160, 162, 168, 180, 183, 192, 196, 200, 204, 216, 220, 224, 240, 243, 252, 256, 272, 280, 288, 294, 300, 320

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OFFSET

1,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..10000 (terms 1..1000 from G. C. Greubel)

MATHEMATICA

Join[{1}, Select[Range[1, 750], Mod[13^#, #] == 1 &]] (* G. C. Greubel, Nov 19 2017 *)

Join[{1}, Select[Range[320], PowerMod[13, #, #] == 1 &]] (* Robert Price, Apr 10 2020 *)

PROG

(PARI) isok(n) = Mod(13, n)^n == 1; \\ Michel Marcus, Nov 19 2017

CROSSREFS

Column k=13 of A333432.

Cf. A116609, A116611, A116620.

Sequence in context: A331728 A353868 A113961 * A036407 A374243 A376154

Adjacent sequences: A116618 A116619 A116620 * A116622 A116623 A116624

KEYWORD

nonn

AUTHOR

Zak Seidov, Feb 19 2006

EXTENSIONS

1 prepended by Max Alekseyev, Jun 28 2011

STATUS

approved