A020213 - OEIS

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

%S 4,6,12,14,21,28,42,84,129,231,259,276,301,341,481,532,651,703,781,

%T 903,1281,1351,1491,1591,1729,2047,2201,2509,2701,2821,3097,3201,3277,

%U 3311,3913,3972,4371,4564,4577,4681,4859,5289,5662,6031,6601,7141,7161,7543

%N Pseudoprimes to base 85.

%C Composite numbers n such that 85^(n-1) == 1 (mod n).

%H T. D. Noe, <a href="/A020213/b020213.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 = 85; 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_