%I #12 Aug 11 2014 22:45:15
%S 15,49,133,481,931,6241,8911,9131,10963,11041,14191,17767,29341,56033,
%T 58969,68251,79003,83333,87061,88183,113527,130561,131407,164737,
%U 190861,197209,206981,210337,229633,244949,264223,269011,270943,347263,389777
%N Strong pseudoprimes to base 31.
%H R. J. Mathar, <a href="/A020257/b020257.txt">Table of n, a(n) for n = 1..698</a>
%H <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a>
%K nonn
%O 1,1
%A _David W. Wilson_