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Pseudoprimes to base 15.
1

%I #13 Aug 03 2014 14:01:10

%S 14,341,742,946,1477,1541,1687,1729,1891,1921,2821,3133,3277,4187,

%T 6541,6601,7471,8701,8911,9073,10279,10649,12871,14041,14701,15409,

%U 15841,16841,19201,20017,24521,25313,25546,28063,29341,30889,31021,38963,41041

%N Pseudoprimes to base 15.

%C Composite numbers n such that 15^(n-1) == 1 (mod n).

%H T. D. Noe, <a href="/A020143/b020143.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 = 15; 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_