%I #9 Jun 13 2018 03:23:55

%S 111,630,3642,21126,122526,710526,4120230,23892558,138549222,

%T 803425470,4658939862,27016470606,156664328166,908472171486,

%U 5268089398710,30548834388078,177147958555782,1027253571178110,5956884336128982

%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 two.

%C Column 2 of A205836.

%H R. H. Hardin, <a href="/A205830/b205830.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 7*a(n-1) -8*a(n-2) +6*a(n-3) for n>4.

%F Empirical g.f.: 3*x*(37 - 49*x + 40*x^2 + 2*x^3) / (1 - 7*x + 8*x^2 - 6*x^3). - _Colin Barker_, Jun 13 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Cf. A205836.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 01 2012