%I
%S 171,2121,24414,285724,3409112,40893800,492154924,5938127608,
%T 71755699992,868144018572,10511898062464,127364674658272,
%U 1543896563706688,18721690171445596,227085751983499944,2755034034648413220
%N Number of (n+1)X3 0..2 arrays with every 2X2 subblock sum equal to exactly one or two horizontal and vertical neighbor 2X2 subblock sums
%C Column 2 of A186871
%H R. H. Hardin, <a href="/A186868/b186868.txt">Table of n, a(n) for n = 1..200</a>
%e Some solutions for 5X3
%e ..0..1..1....0..0..1....0..1..0....0..1..2....0..2..0....0..1..0....0..1..2
%e ..2..1..1....1..2..1....2..2..0....1..1..2....2..2..0....1..1..1....1..2..0
%e ..1..0..0....0..0..1....1..0..1....0..1..2....0..2..0....2..2..2....0..1..2
%e ..0..2..0....1..2..1....0..2..0....2..2..2....0..1..0....0..2..0....2..1..2
%e ..0..1..0....2..1..2....0..2..0....0..1..2....1..0..1....2..0..2....2..1..2
%K nonn
%O 1,1
%A _R. H. Hardin_ Feb 27 2011
