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%I #9 Jun 13 2018 05:47:24
%S 78,300,980,3706,12304,45810,154346,567112,1932816,7031026,24170780,
%T 87268194,301959592,1084079204,3769438358,13475470000,47028047126,
%U 167585570856,586477834058,2084911242168,7311507381518,25945246790130
%N Number of (n+1) X 3 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock equal to one, and every 2 X 2 determinant nonzero.
%C Column 2 of A206010.
%H R. H. Hardin, <a href="/A206004/b206004.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) + 13*a(n-2) - 17*a(n-3) - 34*a(n-4) - 9*a(n-5) + 23*a(n-6) + a(n-7) - 4*a(n-8) + a(n-9).
%F Empirical g.f.: 2*x*(39 + 72*x - 317*x^2 - 414*x^3 - 48*x^4 + 293*x^5 + x^6 - 48*x^7 + 13*x^8) / (1 - 2*x - 13*x^2 + 17*x^3 + 34*x^4 + 9*x^5 - 23*x^6 - x^7 + 4*x^8 - x^9). - _Colin Barker_, Jun 13 2018
%e Some solutions for n=4:
%e ..1..0..2....2..2..1....2..1..2....1..0..1....1..2..2....2..0..2....0..2..0
%e ..1..1..1....2..1..1....0..1..1....1..1..1....1..1..2....2..2..2....1..2..2
%e ..2..1..2....2..2..0....1..1..2....1..2..1....0..1..1....0..1..2....1..1..2
%e ..2..2..2....0..2..2....2..1..1....1..1..1....1..1..0....1..1..1....0..1..1
%e ..1..2..1....1..1..2....2..0..1....1..2..0....0..1..2....0..1..0....1..1..0
%Y Cf. A206010.
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 02 2012
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