%I A140453
%S A140453 1,1,2,3,10,28,164,905,9826,103126,2031252,43437282,1622278624,
%T A140453 66141208960,4579408029576,385335180349569,51207103076632066,
%U A140453 8212830157184175946,2052124795850957537060,683805150345009276656138
%N A140453 Half the number of n X n binary matrices, symmetric under horizontal 
               and vertical reflection, having equal row sums.
%H A140453 Ron Hardin (rhhardin(AT)att.net), Jul 28 2008, <a href="b140453.txt">
               Table of n, a(n) for n = 1..25</a>
%Y A140453 Sequence in context: A089752 A007029 A099435 this_sequence A037169 A058953 
               A160909
%Y A140453 Adjacent sequences: A140450 A140451 A140452 this_sequence A140454 A140455 
               A140456
%K A140453 nonn
%O A140453 1,3
%A A140453 Ron Hardin (rhhardin(AT)att.net), Jul 28 2008