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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 (list; graph; refs; listen; history; text; internal format)
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^(n-1) == 1 (mod n).

REFERENCES

R. Crandall and C. Pomerance, "Prime Numbers - A Computational Perspective", Second Edition, Springer Verlag 2005, ISBN 0-387-25282-7 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, n-1, 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

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Last modified September 22 19:04 EDT 2018. Contains 315270 sequences. (Running on oeis4.)