

A020139


Pseudoprimes to base 11.


2



10, 15, 70, 133, 190, 259, 305, 481, 645, 703, 793, 1105, 1330, 1729, 2047, 2257, 2465, 2821, 4577, 4921, 5041, 5185, 6601, 7869, 8113, 8170, 8695, 8911, 9730, 10585, 12403, 13333, 14521, 14981, 15841, 16705, 17711, 18705, 23377, 24130, 24727, 26335, 26467
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OFFSET

1,1


COMMENTS

According to Karsten Meyer, May 16 2006, 10 should be excluded, following the strict definition in Crandall and Pomerance.
Composite numbers n such that 11^(n1) == 1 (mod n).


REFERENCES

R. Crandall and C. Pomerance, "Prime Numbers  A Computational Perspective", Second Edition, Springer Verlag 2005, ISBN 0387252827 Page 132 (Theorem 3.4.2. and Algorithm 3.4.3)
J.M. De Koninck, Ces nombres qui nous fascinent, Entry 190, p. 57, Ellipses, Paris 2008.


LINKS

R. J. Mathar and T. D. Noe, Table of n, a(n) for n = 1..1000 (R. J. Mathar to 726 terms)
F. Richman, Primality testing with Fermat's little theorem
Index entries for sequences related to pseudoprimes


MATHEMATICA

base = 11; t = {}; n = 1; While[Length[t] < 100, n++; If[! PrimeQ[n] && PowerMod[base, n1, n] == 1, AppendTo[t, n]]]; t (* T. D. Noe, Feb 21 2012 *)


CROSSREFS

Cf. A001567 (pseudoprimes to base 2).
Sequence in context: A047189 A278921 A035407 * A056522 A056511 A166626
Adjacent sequences: A020136 A020137 A020138 * A020140 A020141 A020142


KEYWORD

nonn


AUTHOR

David W. Wilson


STATUS

approved



