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%I #5 Mar 31 2012 12:37:11
%S 4111,2042,12005,6078,36015,18258,108141,54762,324087,163950,971925,
%T 491514,2915439,1474206,8746143,4422606,26238417,13267806,78715239,
%U 39803406,236145705,119410206,708437103,358230606,2125311297,1074691806
%N Number of (n+1)X8 0..3 arrays with every 2X2 subblock having nonzero determinant and commuting with every horizontal or vertical neighbor
%C Column 7 of A206343
%H R. H. Hardin, <a href="/A206342/b206342.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) +3*a(n-2) -3*a(n-3) for n>16
%e Some solutions for n=4
%e ..1..2..0..2..0..2..0..1....3..3..0..1..0..1..0..1....1..3..0..1..0..3..0..1
%e ..1..0..2..0..2..0..2..0....3..0..3..0..1..0..1..0....3..0..3..0..1..0..3..0
%e ..0..1..0..2..0..2..0..2....0..3..0..3..0..1..0..1....0..3..0..3..0..1..0..3
%e ..1..0..1..0..2..0..2..0....1..0..3..0..3..0..1..0....3..0..3..0..3..0..1..0
%e ..0..1..0..1..0..2..0..2....0..1..0..3..0..3..0..1....0..3..0..3..0..3..0..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Feb 06 2012
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