%I #4 May 03 2018 12:51:55
%S 2,5,9,21,53,105,237,577,1205,2681,6349,13681,30309,70377,154429,
%T 342177,783957,1737881,3857581,8760529,19527749,43436873,98090781,
%U 219270657,488654645,1099633401,2461435533,5493590065,12336038693,27628989353
%N Number of nX2 0..1 arrays with every element unequal to 0, 1, 3 or 5 king-move adjacent elements, with upper left element zero.
%C Column 2 of A303969.
%H R. H. Hardin, <a href="/A303963/b303963.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) +8*a(n-3) -4*a(n-4)
%e Some solutions for n=5
%e ..0..1. .0..1. .0..1. .0..0. .0..0. .0..1. .0..1. .0..0. .0..0. .0..0
%e ..0..0. .1..1. .1..1. .0..1. .0..0. .0..0. .1..1. .0..0. .0..1. .1..0
%e ..0..0. .1..1. .1..1. .1..1. .0..1. .0..0. .0..0. .0..0. .0..0. .1..1
%e ..0..0. .1..0. .1..1. .1..1. .1..1. .0..0. .1..0. .1..0. .0..0. .1..1
%e ..1..0. .0..0. .0..1. .0..1. .1..1. .0..1. .1..1. .1..1. .0..1. .1..0
%Y Cf. A303969.
%K nonn
%O 1,1
%A _R. H. Hardin_, May 03 2018