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%I #5 Mar 31 2012 12:37:09
%S 330,2712,22612,189430,1588523,13324720,111764603,937463556,
%T 7863232776,65955006340,553215476117,4640243767418,38921297804723,
%U 326462877927870,2738295489854762,22968191962261382,192651906939967689
%N Number of (n+1)X4 0..2 arrays with the number of clockwise edge increases in every 2X2 subblock equal to two, and every 2X2 determinant nonzero
%C Column 3 of A205998
%H R. H. Hardin, <a href="/A205993/b205993.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 6*a(n-1) +40*a(n-2) -160*a(n-3) -206*a(n-4) +1227*a(n-5) +360*a(n-6) -5565*a(n-7) +4196*a(n-8) +4799*a(n-9) -3146*a(n-10) -3968*a(n-11) -1311*a(n-12) -636*a(n-13) -64*a(n-14) +210*a(n-15) +588*a(n-16) +228*a(n-17) +32*a(n-18) -16*a(n-19) for n>20
%e Some solutions for n=4
%e ..2..0..2..0....2..0..1..2....0..2..0..1....1..2..0..1....1..1..2..1
%e ..2..1..0..1....2..1..0..2....2..0..1..0....2..0..1..0....0..2..1..2
%e ..0..2..1..2....1..2..1..0....0..1..2..1....1..1..2..1....2..0..2..0
%e ..1..0..2..0....2..0..2..1....1..0..1..2....0..2..0..2....0..1..0..1
%e ..2..1..0..2....2..1..0..2....0..1..2..0....1..0..2..0....2..2..1..2
%K nonn
%O 1,1
%A _R. H. Hardin_ Feb 02 2012
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