A262051 Euler pseudoprimes to base 3: composite integers such that abs(3^((n - 1)/2)) == 1 mod n.

121, 703, 1541, 1729, 1891, 2465, 2821, 3281, 4961, 7381, 8401, 8911, 10585, 12403, 15457, 15841, 16531, 18721, 19345, 23521, 24661, 28009, 29341, 30857, 31621, 31697, 41041, 44287, 46657, 47197, 49141, 50881, 52633, 55969, 63139, 63973, 72041, 74593, 75361

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..64 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[26000] + 1, eulerPseudoQ[#, 3] &] (* Michael De Vlieger, Sep 09 2015, after Jean-François Alcover at A006970 *)

Prog

(PARI) for(n=1, 1e5, if( Mod(3, (2*n+1))^n == 1 ||  Mod(3, (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), this sequence (base 3), A001567 (base 4), A262052 (base 5), A262053 (base 6), A262054 (base 7), A262055 (base 8).

Sequence in context: A183885 A036306 A014749 * A048950 A329705 A020229

Adjacent sequences: A262048 A262049 A262050 * A262052 A262053 A262054

Keyword

nonn

Author

Daniel Lignon, Sep 09 2015

Status

approved