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%I #5 Mar 31 2012 12:36:19
%S 56,528,6600,100980,2117870,61630794,2607217770,156166134300,
%T 13953736838272,1844353230617676,367051670671034640,
%U 109228902733245482050,48925662805948380686500
%N Number of (n+2)X(n+2) symmetric binary matrices without the pattern 0 1 1 diagonally or antidiagonally
%H R. H. Hardin, <a href="/A190536/b190536.txt">Table of n, a(n) for n = 1..18</a>
%e Some solutions for 4X4
%e ..1..1..1..0....0..0..1..0....0..1..0..0....1..1..1..1....0..0..0..0
%e ..1..0..0..0....0..0..0..1....1..1..0..0....1..1..1..1....0..1..0..1
%e ..1..0..0..1....1..0..1..0....0..0..0..0....1..1..1..0....0..0..0..0
%e ..0..0..1..0....0..1..0..0....0..0..0..1....1..1..0..0....0..1..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_ May 12 2011
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