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%I A140984 #7 Mar 09 2015 04:31:33
%S A140984 1,2,4,35,226,7592,156752,22458249,1718157826,941605438142,
%T A140984 250228936146872,572800408273738658,580834777459374862880,
%U A140984 5136409738603278958315040,18792196647668946085817284928
%N A140984 Half the number of n X n binary matrices, symmetric under 180 degree rotation, having equal row sums.
%H A140984 R. H. Hardin, Jul 28 2008, <a href="/A140984/b140984.txt">Table of n, a(n) for n = 1..25</a>
%K A140984 nonn
%O A140984 1,2
%A A140984 _R. H. Hardin_, Jul 28 2008

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