%I #8 Feb 18 2018 10:02:29
%S 1,7,10,23,57,122,275,623,1394,3133,7045,15824,35557,79901,179530,
%T 403401,906439,2036744,4576523,10283359,23106492,51919817,116662775,
%U 262138870,589020695,1323517493,2973916806,6682330407,15015060135,33738533866
%N Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 1,3,0,2,4 for x=0,1,2,3,4.
%C Every 0 is next to 0 1's, every 1 is next to 1 3's, every 2 is next to 2 0's, every 3 is next to 3 2's, every 4 is next to 4 4's.
%C Column 2 of A196322.
%H R. H. Hardin, <a href="/A196316/b196316.txt">Table of n, a(n) for n = 1..200</a>
%F Empirical: a(n) = a(n1) +2*a(n2) +2*a(n3) a(n5).
%F Empirical g.f.: x*(1 + 6*x + x^2  3*x^3) / ((1 + x + x^2)*(1  2*x  x^2 + x^3)).  _Colin Barker_, Feb 18 2018
%e Some solutions for n=4:
%e ..0..0....2..0....0..2....0..0....0..2....0..0....0..0....0..2....0..0....0..2
%e ..0..2....0..2....2..0....0..0....0..0....0..0....0..2....0..0....2..2....0..0
%e ..0..2....0..2....2..0....0..0....0..0....0..0....0..2....0..0....0..0....0..0
%e ..2..0....0..0....0..2....0..2....0..2....2..0....0..0....0..0....2..0....2..0
%K nonn
%O 1,2
%A _R. H. Hardin_, Oct 01 2011
