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%I #5 Mar 31 2012 12:37:34
%S 0,1,100,6684,599536,82309141,18679289180,7191882371599,
%T 4794826023217991,5595844097524199026,11523237615776387849625,
%U 42103142637653897079485507
%N Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having two distinct values, and new values 0..3 introduced in lower triangle row major order
%e Some solutions for n=3
%e ..0..1..0..2....0..1..0..1....0..0..0..0....0..1..1..2....0..1..2..0
%e ..1..1..0..0....1..0..0..0....0..1..0..2....1..1..2..1....1..1..2..2
%e ..0..0..0..3....0..0..2..2....0..0..0..0....1..2..2..2....2..2..1..1
%e ..2..0..3..3....1..0..2..3....0..2..0..3....2..1..2..3....0..2..1..3
%K nonn
%O 1,3
%A _R. H. Hardin_ Mar 27 2012