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A020185 Pseudoprimes to base 57. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 8 19:29 EDT 2020. Contains 336298 sequences. (Running on oeis4.)