%I #7 Feb 21 2018 14:29:21
%S 0,1,2,5,10,25,54,125,282,641,1454,3301,7490,17001,38582,87565,198730,
%T 451025,1023614,2323125,5272402,11965881,27156934,61633501,139879130,
%U 317460001,720485262,1635163525,3711054050,8422351625,19114786774
%N Number of n X 2 0..1 arrays with every element equal to 2, 3 or 4 king-move adjacent elements, with upper left element zero.
%C Column 2 of A297866.
%H R. H. Hardin, <a href="/A297860/b297860.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-2) + 4*a(n-3) + 2*a(n-4).
%F Empirical g.f.: x^2*(1 + 2*x + 2*x^2) / ((1 + x)*(1 - x - 2*x^2 - 2*x^3)). - _Colin Barker_, Feb 21 2018
%e Some solutions for n=7:
%e ..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0
%e ..1..0. .0..0. .0..0. .1..0. .1..0. .1..0. .0..0. .0..0. .0..0. .0..0
%e ..1..1. .1..1. .0..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1
%e ..1..1. .1..1. .1..1. .0..0. .0..0. .1..0. .1..0. .1..1. .0..1. .1..0
%e ..0..0. .0..0. .1..1. .0..1. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0
%e ..0..1. .0..1. .0..1. .1..1. .1..1. .1..0. .0..1. .1..0. .1..1. .1..0
%e ..1..1. .1..1. .0..0. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1. .1..1
%Y Cf. A297866.
%K nonn
%O 1,3
%A _R. H. Hardin_, Jan 07 2018