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A020153 Pseudoprimes to base 25. 1

%I

%S 4,6,8,12,24,28,39,66,91,124,217,232,276,403,426,451,532,561,616,703,

%T 781,804,868,946,1128,1288,1541,1729,1891,2047,2701,2806,2821,2911,

%U 2926,3052,3126,3367,3592,3976,4069,4123,4207,4564,4636,4686,5321,5461,5551,5611

%N Pseudoprimes to base 25.

%C Composite numbers n such that 25^(n-1) == 1 (mod n).

%H T. D. Noe, <a href="/A020153/b020153.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 = 25; 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 November 17 13:33 EST 2019. Contains 329230 sequences. (Running on oeis4.)