A020156 - OEIS

A020156

Pseudoprimes to base 28.

9, 27, 45, 87, 145, 261, 361, 529, 561, 703, 783, 785, 1105, 1305, 1413, 1431, 1885, 2041, 2413, 2465, 2871, 3201, 3277, 4553, 4699, 5149, 5181, 5365, 7065, 8149, 8321, 8401, 9841, 10027, 10585, 12673, 13333, 13345, 13357, 13833, 14383, 14769, 14981

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OFFSET

1,1

COMMENTS

Composite numbers n such that 28^(n-1) == 1 (mod n). - Michel Lagneau, Feb 18 2012

LINKS

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

Index entries for sequences related to pseudoprimes

MATHEMATICA

base = 28; 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: A069069 A354815 A031088 * A342869 A287661 A062231

Adjacent sequences: A020153 A020154 A020155 * A020157 A020158 A020159

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved