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A020209 Pseudoprimes to base 81. 1
4, 8, 10, 16, 20, 28, 40, 52, 70, 80, 85, 91, 112, 121, 130, 176, 190, 205, 208, 232, 280, 286, 292, 364, 370, 451, 496, 511, 520, 532, 616, 671, 697, 703, 730, 742, 910, 946, 949, 965, 976, 1036, 1105, 1168, 1261, 1288, 1387, 1435, 1456, 1541, 1606, 1729, 1891 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Composite numbers n such that 81^(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 = 81; 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 *)

CROSSREFS

Cf. A001567 (pseudoprimes to base 2).

Sequence in context: A311004 A144570 A036311 * A311005 A311006 A311007

Adjacent sequences:  A020206 A020207 A020208 * A020210 A020211 A020212

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified May 25 19:30 EDT 2020. Contains 334595 sequences. (Running on oeis4.)