%I #7 Mar 09 2015 04:30:30
%S 1,1,2,3,10,28,164,905,9826,103126,2031252,43437282,1622278624,
%T 66141208960,4579408029576,385335180349569,51207103076632066,
%U 8212830157184175946,2052124795850957537060,683805150345009276656138
%N Half the number of n X n binary matrices, symmetric under horizontal and vertical reflection, having equal row sums.
%H R. H. Hardin, Jul 28 2008, <a href="/A140453/b140453.txt">Table of n, a(n) for n = 1..25</a>
%K nonn
%O 1,3
%A _R. H. Hardin_, Jul 28 2008