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Number of (n+1)X8 0..2 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors
1

%I #5 Mar 31 2012 12:36:05

%S 3078,2937,9982,14883,40626,49407,136086,170811,431658,564459,1356918,

%T 1931673,4382606,6664633,14283484,22714258,46720546,76914734,

%U 153497652,259317918,505928220,871401594,1671620876,2921206834,5533505212

%N Number of (n+1)X8 0..2 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors

%C Column 7 of A186472

%H R. H. Hardin, <a href="/A186470/b186470.txt">Table of n, a(n) for n = 1..82</a>

%F Empirical: a(n)=2*a(n-1)+a(n-2)-4*a(n-3)+4*a(n-4)-2*a(n-5) for n>16

%e Some solutions for 3X8

%e ..0..2..0..2..0..0..0..0....2..0..0..0..0..0..0..2....1..2..0..0..0..2..0..2

%e ..1..0..2..0..2..0..0..0....0..2..0..0..0..0..0..2....1..0..2..0..0..0..2..0

%e ..0..1..0..2..0..2..2..2....1..0..2..0..0..0..0..2....0..1..0..2..0..0..0..2

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 22 2011