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 A020145 Pseudoprimes to base 17. 2

%I

%S 4,8,9,16,45,91,145,261,781,1111,1228,1305,1729,1885,2149,2821,3991,

%T 4005,4033,4187,4912,5365,5662,5833,6601,6697,7171,8481,8911,10585,

%U 11476,12403,12673,13333,13833,15805,15841,16705,19345,19729,20591,21781,22791

%N Pseudoprimes to base 17.

%C According to _Karsten Meyer_, May 16 2006, 4, 8, 9 and 16 should be excluded, following the strict definition in Crandall and Pomerance.

%D 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)

%D Composite numbers n such that 17^(n-1) == 1 (mod n).

%H R. J. Mathar and T. D. Noe, <a href="/A020145/b020145.txt">Table of n, a(n) for n = 1..1000</a> (R. J. Mathar to 799 terms)

%H F. Richman, <a href="http://math.fau.edu/Richman/carm.htm">Primality testing with Fermat's little theorem</a>

%H <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>

%t base = 17; 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 *)

%Y Cf. A001567 (pseudoprimes to base 2).

%K nonn

%O 1,1

%A _David W. Wilson_

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Last modified September 20 01:09 EDT 2017. Contains 292251 sequences.