%I #13 Aug 03 2014 14:01:12
%S 4,38,39,57,65,76,247,285,703,741,969,1105,1387,1513,1653,1891,2465,
%T 2701,2806,2965,3705,4033,4371,4636,5073,5461,5713,5785,6305,6441,
%U 6533,6541,7633,7709,7957,10081,10585,10777,11229,12871,13051,16017,16745,17081
%N Pseudoprimes to base 77.
%C Composite numbers n such that 77^(n-1) == 1 (mod n).
%H T. D. Noe, <a href="/A020205/b020205.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 = 77; 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_