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%I #6 Mar 31 2012 12:36:05
%S 4096,4834,269126,1024481,21122896,70300633,1381305433,5019710665,
%T 92758821369,358905890921,6225263778969,25517863738777,
%U 418350075763113,1809120677086713,28157232600156937,127921801557860825
%N Number of (n+1)X(n+1) 0..7 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors
%C Diagonal of A186490
%H R. H. Hardin, <a href="/A186489/b186489.txt">Table of n, a(n) for n = 1..20</a>
%e Some solutions for 3X3
%e ..6..0..6....7..4..0....3..6..3....3..5..0....6..7..0....5..4..0....5..0..0
%e ..0..6..0....1..0..4....6..3..6....1..0..5....5..0..7....0..0..4....0..0..0
%e ..3..0..6....0..1..5....3..6..3....0..1..4....0..5..7....0..0..3....0..0..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Feb 22 2011
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