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A343930
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Numbers k such that Sum_{j=1..k} (-j)^j == 1 (mod k).
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2
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1, 2, 30, 33, 37, 83, 149, 262, 4030, 31969, 140225, 182730, 724754, 2337094, 3985753, 4195221, 4541725
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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q[n_] := n == 1 || Mod[Sum[PowerMod[-k, k, n], {k, 1, n}], n] == 1; Select[Range[5000], q] (* Amiram Eldar, May 04 2021 *)
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PROG
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(PARI) isok(n) = sum(k=1, n, Mod(-k, n)^k)==1;
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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