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 A235363 (1 + Sum_{k=1..m-1} k^(m-1)) (mod m), for m = 1, 3, 5, 7, 9, ... 2
 0, 0, 0, 0, 7, 0, 0, 11, 0, 0, 15, 0, 21, 19, 0, 0, 23, 1, 0, 27, 0, 0, 22, 0, 43, 35, 0, 1, 39, 0, 0, 43, 53, 0, 47, 0, 0, 51, 1, 0, 55, 0, 69, 59, 0, 79, 63, 1, 0, 67, 0, 0, 50, 0, 0, 75, 0, 1, 79, 1, 111, 83, 101, 0, 87, 0, 115, 91, 0, 0, 95, 1, 117, 99, 0, 0, 103, 1, 0, 107, 1, 0, 78, 0, 157, 115, 0, 151, 119, 0, 0, 123, 149, 1, 127, 0, 0, 131, 0, 0, 135 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS a(n) = (1 + Sum_{k=1..2*n} k^(2*n)) (mod 2*n+1), for n = 0, 1, 2, 3, ... The Agoh-Giuga Conjecture is that a(n)=0 iff 2*n+1 is 1 or a prime. LINKS MathWorld, Giuga's Conjecture Wikipedia, Agoh-Giuga conjecture FORMULA a(n) = 0 iff A235364(n) = 0. MATHEMATICA Table[ Mod[ Sum[ PowerMod[ k, n - 1, n], {k, n - 1}] + 1, n], {n, 1, 201, 2}] CROSSREFS Cf. A007850, A046094, A204187, A228037, A235364. Sequence in context: A154102 A344785 A240984 * A356592 A211904 A094898 Adjacent sequences: A235360 A235361 A235362 * A235364 A235365 A235366 KEYWORD nonn AUTHOR Jonathan Sondow, Jan 07 2014 STATUS approved

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Last modified November 29 08:47 EST 2022. Contains 358422 sequences. (Running on oeis4.)