%I #7 Aug 06 2018 05:33:34
%S 0,4,8,73,292,1713,8235,43733,220672,1142790,5840082,30047605,
%T 154064032,791329272,4060908537,20849136414,107016685715,549372170263,
%U 2820041046796,14476302849381,74310986678816,381462539353767
%N Number of 2 X n arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, without consecutive moves in the same direction.
%C Row 2 of A221483.
%H R. H. Hardin, <a href="/A221484/b221484.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) + 17*a(n-2) + 22*a(n-3) + a(n-4) - 14*a(n-5) - 2*a(n-6) + a(n-7).
%F Empirical g.f.: x^2*(1 - x)*(4 + 8*x + 5*x^2) / ((1 + 3*x + x^2)*(1 - 4*x - 6*x^2 + 5*x^4 - x^5)). - _Colin Barker_, Aug 06 2018
%e Some solutions for n=3:
%e ..1..1..1....0..1..1....1..2..1....0..3..1....0..3..0....0..2..0....1..2..0
%e ..0..3..0....1..3..0....0..2..0....1..1..0....1..1..1....1..2..1....0..2..1
%Y Cf. A221483.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 17 2013