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Pseudoprimes to base 16.
1

%I #19 Jun 13 2018 03:43:19

%S 15,51,85,91,255,341,435,451,561,595,645,703,1105,1247,1261,1271,1285,

%T 1387,1581,1687,1695,1729,1891,1905,2047,2071,2091,2431,2465,2701,

%U 2821,3133,3277,3367,3655,3683,4033,4369,4371,4681,4795,4859,5083,5151,5461

%N Pseudoprimes to base 16.

%C Composite numbers n such that 16^(n-1) == 1 (mod n). - _Michel Lagneau_, Feb 18 2012

%H T. D. Noe, <a href="/A020144/b020144.txt">Table of n, a(n) for n = 1..1000</a>

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

%t base = 16; 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_