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%I #5 Mar 31 2012 12:36:07
%S 405,19062,267840,5755698,99203418,1921749372,34994620836,
%T 658156407930,12168728064540,227006548039242,4215046606416756,
%U 78456814617739176,1458483057478165140,27130892560870689198,504514738674275619150
%N Number of (n+1)X4 0..2 arrays with every 2X2 subblock trace equal to exactly one or two horizontal and vertical neighbor 2X2 subblock traces
%C Column 3 of A187140
%H R. H. Hardin, <a href="/A187134/b187134.txt">Table of n, a(n) for n = 1..200</a>
%e Some solutions for 6X4
%e ..0..0..0..0....2..0..0..0....1..0..0..0....1..0..0..0....0..0..0..0
%e ..2..0..0..0....1..0..0..0....1..0..0..0....1..0..0..0....2..0..0..0
%e ..2..0..1..0....2..1..0..0....1..0..0..0....2..0..1..0....2..0..1..0
%e ..0..0..1..0....1..0..0..2....0..0..1..1....2..0..2..2....0..0..1..2
%e ..2..2..2..2....2..1..1..2....0..0..2..2....1..1..2..1....2..2..2..2
%e ..0..1..1..1....1..0..1..1....0..0..2..1....0..2..2..1....1..2..2..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 05 2011