%I #4 Aug 07 2018 22:04:26
%S 1,5,16,50,160,511,1634,5226,16716,53471,171045,547149,1750258,
%T 5598852,17910021,57291907,183269625,586256561,1875361283,5999045795,
%U 19190195958,61387032829,196369427849,628161199864,2009408986694,6427847623748
%N Number of nX2 0..1 arrays with every element unequal to 1, 2 or 3 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.
%C Column 2 of A317823.
%H R. H. Hardin, <a href="/A317817/b317817.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) +a(n-2) -3*a(n-4) -2*a(n-5) -a(n-6)
%e Some solutions for n=5
%e ..0..1. .0..1. .0..0. .0..1. .0..1. .0..0. .0..1. .0..0. .0..1. .0..1
%e ..0..1. .0..0. .1..1. .0..1. .1..1. .1..1. .0..1. .1..0. .1..0. .1..1
%e ..1..1. .1..0. .0..0. .0..0. .0..0. .0..1. .0..0. .1..0. .1..0. .1..0
%e ..0..0. .1..0. .1..1. .1..1. .1..1. .0..0. .0..1. .0..0. .1..0. .0..1
%e ..1..0. .1..0. .0..0. .0..1. .0..1. .0..1. .1..0. .0..1. .1..1. .0..1
%Y Cf. A317823.
%K nonn
%O 1,2
%A _R. H. Hardin_, Aug 07 2018