%I #5 Mar 31 2012 12:36:07
%S 0,1773,267840,201302208,440941355208,3703181282209854
%N Number of (n+1)X(n+1) 0..2 arrays with every 2X2 subblock trace equal to exactly one or two horizontal and vertical neighbor 2X2 subblock traces
%C Diagonal of A187140
%e Some solutions for 4X4
%e ..0..1..1..0....0..1..2..0....2..1..1..0....1..0..2..0....2..1..1..0
%e ..1..1..1..1....1..2..2..2....2..1..0..0....2..1..1..1....1..1..2..2
%e ..1..0..0..0....0..1..1..2....0..1..0..1....0..0..0..2....2..2..1..0
%e ..0..1..2..2....0..2..2..2....1..2..1..2....2..2..1..1....0..2..2..1
%K nonn
%O 1,2
%A _R. H. Hardin_ Mar 05 2011