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Pseudoprimes to base 72.
1

%I #18 Jun 13 2018 09:15:56

%S 85,305,365,451,511,781,793,949,1037,1105,1241,1387,1541,1729,2465,

%T 2485,2501,2701,2821,2911,4381,4411,4453,5183,5185,5257,6205,6601,

%U 6697,8449,8911,9061,10585,11305,13213,13981,14111,15841,16441,17803,18721,19345

%N Pseudoprimes to base 72.

%C Composite numbers n such that 72^(n-1) == 1 (mod n). - _Michel Lagneau_, Feb 18 2012

%H T. D. Noe, <a href="/A020200/b020200.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 = 72; 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_