A020185 Pseudoprimes to base 57.

4, 8, 14, 25, 28, 56, 65, 125, 145, 203, 217, 325, 377, 451, 721, 725, 781, 1001, 1105, 1625, 1885, 1891, 2047, 2296, 2465, 2701, 2821, 2911, 3193, 3277, 3565, 3625, 3976, 4141, 4187, 5365, 5425, 6461, 6533, 6601, 7501, 7613, 8029, 8401, 9373, 9425, 10325

Offset

1,1

Comments

Composite numbers n such that 57^(n-1) == 1 (mod n).

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Index entries for sequences related to pseudoprimes

Mathematica

base = 57; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n-1, n] == 1, AppendTo[t, n]]]; t (* T. D. Noe, Feb 21 2012 *)

Prog

(PARI) isA020185(n) = (Mod(57, n)^(n-1)==1) && (!isprime(n))

Crossrefs

Cf. A001567 (pseudoprimes to base 2).

Sequence in context: A131831 A100314 A105143 * A008029 A129080 A138643

Adjacent sequences: A020182 A020183 A020184 * A020186 A020187 A020188

Keyword

nonn

Author

David W. Wilson

Status

approved