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A343930 Numbers k such that Sum_{j=1..k} (-j)^j == 1 (mod k). 2
1, 2, 30, 33, 37, 83, 149, 262, 4030, 31969, 140225, 182730, 724754, 2337094, 3985753, 4195221, 4541725 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..17.

MATHEMATICA

q[n_] := n == 1 || Mod[Sum[PowerMod[-k, k, n], {k, 1, n}], n] == 1; Select[Range[5000], q] (* Amiram Eldar, May 04 2021 *)

PROG

(PARI) isok(n) = sum(k=1, n, Mod(-k, n)^k)==1;

CROSSREFS

Cf. A188776, A341437, A343931, A343933.

Sequence in context: A073418 A022377 A145290 * A127026 A105962 A113695

Adjacent sequences:  A343927 A343928 A343929 * A343931 A343932 A343933

KEYWORD

nonn,more

AUTHOR

Seiichi Manyama, May 04 2021

EXTENSIONS

a(11)-a(13) from Chai Wah Wu, May 04 2021

a(14) from Martin Ehrenstein, May 05 2021

a(15)-a(17) from Martin Ehrenstein, May 08 2021

STATUS

approved

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Last modified July 26 12:20 EDT 2021. Contains 346294 sequences. (Running on oeis4.)