%I #8 Jul 13 2018 05:33:19
%S 204,3171,49056,759642,11761044,182095128,2819342124,43651363500,
%T 675845981124,10463998747116,162012162212700,2508404424354996,
%U 38837163012482148,601308631223158716,9309950622871199676
%N Half the number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock having exactly one duplicate clockwise edge difference.
%C Column 2 of A209796.
%H R. H. Hardin, <a href="/A209790/b209790.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 14*a(n-1) + 27*a(n-2) - 64*a(n-3) + 22*a(n-4).
%F Empirical g.f.: 3*x*(68 + 105*x - 282*x^2 + 99*x^3) / (1 - 14*x - 27*x^2 + 64*x^3 - 22*x^4). - _Colin Barker_, Jul 13 2018
%e Some solutions for n=4.
%e ..1..1..1....2..0..1....1..2..0....0..0..2....0..0..2....2..0..2....2..0..1
%e ..1..0..0....0..0..0....0..2..0....0..1..1....0..1..1....2..2..2....2..0..2
%e ..1..2..2....2..2..1....2..2..1....0..1..2....1..1..0....0..2..1....1..0..2
%e ..0..0..0....2..0..0....2..0..1....0..0..2....1..2..2....2..2..1....1..2..2
%e ..2..0..2....2..0..1....0..0..2....0..2..2....0..0..1....2..0..0....2..2..1
%Y Cf. A209796.
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 13 2012