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Pseudoprimes to base 69.
1

%I #13 Aug 03 2014 14:01:12

%S 4,34,35,68,85,91,119,133,247,361,595,1105,1387,1615,1729,1921,2431,

%T 2465,2527,2701,2821,3605,3655,4187,4693,4849,5713,6161,6643,6943,

%U 7345,7735,8911,10349,10585,11191,11305,11905,13019,13357,14246,14315,15181,15841

%N Pseudoprimes to base 69.

%C Composite numbers n such that 69^(n-1) == 1 (mod n).

%H T. D. Noe, <a href="/A020197/b020197.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 = 69; 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_