%I #6 Mar 31 2012 12:36:05
%S 19683,173,1399,8983,21007,29935,47719,82783,168391,441199,1129591,
%T 2679679,6669991,15566383,34790167,83037151,194778055,446546575,
%U 1070609527,2528845759,5841194023,13884206959,32712096727,75846181663
%N Number of (n+2)X(n+2) 0..2 arrays with every 3X3 subblock commuting with each horizontal and vertical neighbor 3X3 subblock
%C Diagonal of A186568
%H R. H. Hardin, <a href="/A186559/b186559.txt">Table of n, a(n) for n = 1..26</a>
%e Some solutions for 4X4
%e ..0..0..0..0....0..0..0..0....2..1..1..2....0..1..0..0....0..0..0..0
%e ..0..0..0..0....0..0..0..0....1..2..1..1....0..0..1..0....1..0..0..0
%e ..1..0..0..0....0..0..0..0....1..1..2..1....1..0..0..1....2..1..0..0
%e ..2..0..0..0....1..1..1..1....2..1..1..2....0..1..0..0....1..2..1..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Feb 23 2011