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%I #6 Mar 31 2012 17:16:17
%S 10,184,6304,416368,54050896,13894956304,7116012826192,
%T 7287811488547552,14966388560597031328,61754027537691698147200,
%U 512742718215616709255295136,8576912248102024129584312864160
%N 1/4 the number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having one or two distinct values
%H R. H. Hardin, <a href="/A211102/b211102.txt">Table of n, a(n) for n = 1..13</a>
%e Some solutions for n=3
%e ..1..2..2..2....2..0..0..1....3..1..2..0....2..3..3..2....1..2..3..3
%e ..2..2..2..3....0..0..0..0....1..1..2..2....3..3..3..3....2..2..2..2
%e ..2..2..2..2....0..0..2..0....2..2..2..1....3..3..3..3....3..2..3..3
%e ..2..3..2..0....1..0..0..0....0..2..1..2....2..3..3..1....3..2..3..3
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 31 2012
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