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%I #8 Mar 09 2020 20:55:01
%S 1,232,66178,24243520,11234051976,6549149852112,4762109992158288,
%T 4274712091685443584,4686484162304929219950,6209619146419137708859600,
%U 9845751579221258486943505348,18509102695712474753650903363840,40904306737052771732376660591663712
%N Number of n X n symmetric binary matrices with all row sums 6.
%H Andrew Howroyd, <a href="/A139673/b139673.txt">Table of n, a(n) for n = 6..25</a>
%Y Column k=6 of A333157 and row 6 of A188448.
%K nonn
%O 6,2
%A _R. H. Hardin_, Jun 12 2008
%E Terms a(13) and beyond from _Andrew Howroyd_, Mar 09 2020