%I #8 Jun 11 2018 14:49:34
%S 50,275,1562,8948,51458,296774,1716002,9946442,57787010,336482834,
%T 1963466114,11480698658,67259440130,394759998530,2320933378562,
%U 13667740361858,80610335471618,476103197966594,2815694162688002
%N Number of (n+1) X 3 0..2 arrays with every 2 X 2 subblock having the same number of equal diagonal or antidiagonal elements, and new values 0..2 introduced in row major order.
%C Column 2 of A205361.
%H R. H. Hardin, <a href="/A205355/b205355.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 15*a(n-1) - 76*a(n-2) + 146*a(n-3) - 84*a(n-4).
%F Empirical g.f.: x*(50 - 475*x + 1237*x^2 - 882*x^3) / ((1 - x)*(1 - 6*x)*(1 - 8*x + 14*x^2)). - _Colin Barker_, Jun 11 2018
%e Some solutions for n=4:
%e ..0..0..0....0..0..1....0..1..2....0..1..2....0..0..0....0..1..0....0..1..1
%e ..1..0..1....2..2..1....0..1..0....2..0..1....0..0..0....2..1..2....2..2..2
%e ..2..1..2....1..0..1....0..2..2....0..0..0....0..0..0....2..1..2....1..1..1
%e ..1..0..1....2..0..1....1..1..0....2..0..1....0..0..0....0..1..2....0..2..2
%e ..0..2..0....1..0..2....2..2..2....1..2..0....0..0..0....0..1..2....0..1..1
%Y Cf. A205361.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 26 2012