%I #11 Aug 07 2015 03:41:05
%S 55,57,247,1027,1501,1705,1891,3193,3277,5665,12403,18721,19513,19517,
%T 20329,38963,46717,76049,79213,90973,118301,128627,135097,137299,
%U 144523,163073,175615,188501,196981,197633,211411,218791,226651,235183,250849
%N Strong pseudoprimes to base 56.
%H R. J. Mathar, <a href="/A020282/b020282.txt">Table of n, a(n) for n = 1..300</a>
%H <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%K nonn
%O 1,1
%A _David W. Wilson_