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A262054 Euler pseudoprimes to base 7: composite integers such that abs(7^((n - 1)/2)) == 1 mod n. 6
25, 325, 703, 817, 1825, 2101, 2353, 2465, 3277, 4525, 6697, 8321, 10225, 11041, 11521, 12025, 13665, 14089, 19345, 20197, 20417, 20425, 25829, 29857, 29891, 35425, 38081, 39331, 46657, 49241, 49321, 50881, 58825, 64681, 75241, 75361, 76627, 78937, 79381 (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..61 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[25000] + 1, eulerPseudoQ[#, 7] &] (* Michael De Vlieger, Sep 09 2015, after Jean-Fran├žois Alcover at A006970 *)

PROG

(PARI) for(n=1, 1e5, if( Mod(7, (2*n+1))^n == 1 ||  Mod(7, (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), this sequence (base 7), A262055 (base 8).

Sequence in context: A162367 A263404 A077503 * A020275 A020233 A020319

Adjacent sequences:  A262051 A262052 A262053 * A262055 A262056 A262057

KEYWORD

nonn

AUTHOR

Daniel Lignon, Sep 09 2015

STATUS

approved

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Last modified October 20 22:44 EDT 2019. Contains 328291 sequences. (Running on oeis4.)