%I A140217
%S A140217 1,1,2,9,34,730,4376,905345,10601986,10009765626,200097656252,
%T A140217 2177748514672962,85812416258106784,4142789042980129347156,
%U A140217 289904403212517959978240,175519033940460517461369847809
%N A140217 Half the number of n X n binary matrices, symmetric under horizontal 
               reflection, having equal row sums.
%H A140217 Ron Hardin (rhhardin(AT)att.net), Jul 28 2008, <a href="b140217.txt">
               Table of n, a(n) for n = 1..25</a>
%Y A140217 Sequence in context: A150943 A150944 A151308 this_sequence A032601 A083141 
               A001571
%Y A140217 Adjacent sequences: A140214 A140215 A140216 this_sequence A140218 A140219 
               A140220
%K A140217 nonn
%O A140217 1,3
%A A140217 Ron Hardin (rhhardin(AT)att.net), Jul 28 2008