A020225 - OEIS

%I #15 Aug 03 2014 14:01:13

%S 4,6,8,12,16,21,24,32,48,49,66,96,105,147,176,186,231,245,341,344,469,

%T 481,496,561,637,645,651,833,946,949,973,1056,1065,1068,1105,1128,

%U 1729,1813,1891,2046,2047,2465,2701,2821,2976,3053,3277,3283,3577,4187

%N Pseudoprimes to base 97.

%C Composite numbers n such that 97^(n-1) == 1 (mod n).

%H T. D. Noe, <a href="/A020225/b020225.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 = 97; 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_