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 A046116 Numbers k such that no Paley-type Hadamard matrix of order k exists. 1
 92, 116, 156, 172, 184, 188, 232, 236, 260, 268, 292, 324, 356, 372, 376, 404, 412, 428, 436, 452, 472, 476, 508, 520, 532, 536, 584, 596, 604, 612, 652, 668, 712, 716, 732, 756, 764, 772, 808, 836, 852, 856, 872, 876, 892, 904, 932, 940, 944, 952, 956 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Joerg Arndt, Matters Computational (The Fxtbook). Eric Weisstein's World of Mathematics, Hadamard Matrix. Eric Weisstein's World of Mathematics, Paley Class. FORMULA Divisible by 4 but not of form 2^a*(q+1), q = odd prime power. PROG (PARI) isp(k) = for (i=0, valuation(k, 2), if (isprimepower(k/2^i-1, &p) && (p%2), return(1)); ); return(0); isok(k) = !(k%4) && !isp(k); \\ Michel Marcus, Mar 05 2023 CROSSREFS Subsequence of A008586. Sequence in context: A252075 A065511 A252068 * A273286 A257761 A252067 Adjacent sequences: A046113 A046114 A046115 * A046117 A046118 A046119 KEYWORD nonn AUTHOR STATUS approved

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Last modified March 23 15:48 EDT 2023. Contains 361445 sequences. (Running on oeis4.)