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A262052 Euler pseudoprimes to base 5: composite integers such that abs(5^((n - 1)/2)) == 1 mod n. 6
217, 781, 1541, 1729, 5461, 5611, 6601, 7449, 7813, 11041, 12801, 13021, 13333, 14981, 15751, 15841, 16297, 21361, 23653, 24211, 25351, 29539, 30673, 38081, 40501, 41041, 44173, 44801, 46657, 47641, 48133, 53971, 56033, 67921, 75361, 79381, 90241, 98173, 100651, 102311 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000 (term 1..65 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[27000] + 1, eulerPseudoQ[#, 5] &] (* Michael De Vlieger, Sep 09 2015, after Jean-Fran├žois Alcover at A006970 *)

PROG

(PARI) for(n=1, 1e5, if( Mod(5, (2*n+1))^n == 1 ||  Mod(5, (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), this sequence (base 5), A262053 (base 6), A262054 (base 7), A262055 (base 8).

Sequence in context: A019422 A231558 A101826 * A020251 A320715 A183778

Adjacent sequences:  A262049 A262050 A262051 * A262053 A262054 A262055

KEYWORD

nonn

AUTHOR

Daniel Lignon, Sep 09 2015

STATUS

approved

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Last modified November 21 15:00 EST 2019. Contains 329371 sequences. (Running on oeis4.)