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 A262055 Euler pseudoprimes to base 8: composite integers such that abs(8^((n - 1)/2)) == 1 mod n. 6
 9, 21, 65, 105, 133, 273, 341, 481, 511, 561, 585, 1001, 1105, 1281, 1417, 1541, 1661, 1729, 1905, 2047, 2465, 2501, 3201, 3277, 3641, 4033, 4097, 4641, 4681, 4921, 5461, 6305, 6533, 6601, 7161, 8321, 8481, 9265, 9709, 10261, 10585, 10745, 11041, 12545 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..182 from Daniel Lignon) MATHEMATICA eulerPseudoQ[n_?PrimeQ, b_] = False; eulerPseudoQ[n_, b_] := Block[{p = PowerMod[b, (n - 1)/2, n]}, p == Mod[1, n] || p == Mod[-1, n]]; Select[2 Range[11000] + 1, eulerPseudoQ[#, 8] &] (* Michael De Vlieger, Sep 09 2015, after Jean-François Alcover at A006970 *) PROG (PARI) for(n=1, 1e5, if( Mod(8, (2*n+1))^n == 1 ||  Mod(8, (2*n+1))^n == 2*n && bigomega(2*n+1) != 1 , print1(2*n+1", "))); \\ Altug Alkan, Oct 11 2015 CROSSREFS Cf. A006970 (base 2), A262051 (base 3), A262052 (base 5), A262053 (base 6), A262054 (base 7), this sequence (base 8). Sequence in context: A020290 A020288 A147466 * A193276 A173084 A137340 Adjacent sequences:  A262052 A262053 A262054 * A262056 A262057 A262058 KEYWORD nonn AUTHOR Daniel Lignon, Sep 09 2015 STATUS approved

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Last modified February 28 08:41 EST 2020. Contains 332323 sequences. (Running on oeis4.)