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 A176817 Nonprimes such that (2^(n-1) mod n)=(4^(n-1) mod n). 1
 1, 4, 8, 16, 28, 32, 64, 112, 128, 256, 341, 448, 496, 512, 561, 645, 1016, 1024, 1105, 1288, 1387, 1729, 1792, 1905, 2044, 2047, 2048, 2416, 2465, 2701, 2821, 3277, 4033, 4096, 4369, 4371, 4672, 4681, 4984, 5461, 6601, 7168, 7936, 7957, 8128, 8192, 8321, 8481, 8911 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS All powers of two are present. LINKS MATHEMATICA fQ[n_] := !PrimeQ@ n && PowerMod[2, n - 1, n] == PowerMod[4, n - 1, n]; Select[ Range@ 10000, fQ] CROSSREFS Cf. A062173, A062175, A176176. Sequence in context: A273029 A273080 A020193 * A050856 A271649 A128441 Adjacent sequences:  A176814 A176815 A176816 * A176818 A176819 A176820 KEYWORD nonn AUTHOR Juri-Stepan Gerasimov, Dec 07 2010 STATUS approved

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Last modified May 23 11:20 EDT 2019. Contains 323514 sequences. (Running on oeis4.)