%I #4 Jan 06 2018 10:54:14
%S 1,4,17,49,166,573,1933,6538,22165,75089,254350,861661,2919029,
%T 9888610,33499125,113483321,384441606,1302353053,4411914717,
%U 14946017274,50631856149,171522942625,581059476926,1968425392285,6668333757637
%N Number of nX2 0..1 arrays with every element equal to 1, 2 or 3 king-move adjacent elements, with upper left element zero.
%C Column 2 of A297823.
%H R. H. Hardin, <a href="/A297817/b297817.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) +a(n-2) +2*a(n-3) -2*a(n-4) -4*a(n-5) for n>6
%e Some solutions for n=7
%e ..0..1. .0..0. .0..1. .0..0. .0..1. .0..1. .0..0. .0..0. .0..1. .0..1
%e ..1..0. .1..1. .0..1. .1..1. .1..0. .0..1. .1..0. .1..0. .1..0. .0..1
%e ..1..0. .0..0. .0..1. .1..0. .1..1. .0..0. .0..1. .1..0. .0..0. .1..0
%e ..1..1. .0..0. .0..1. .0..0. .0..0. .0..1. .0..0. .0..0. .0..1. .0..1
%e ..1..0. .1..1. .0..1. .1..0. .1..0. .0..1. .1..0. .1..0. .1..0. .0..1
%e ..0..1. .0..1. .0..1. .1..0. .1..0. .0..1. .1..0. .0..1. .0..0. .1..0
%e ..1..0. .0..1. .0..1. .1..0. .0..1. .0..1. .0..1. .0..1. .1..1. .1..0
%Y Cf. A297823.
%K nonn
%O 1,2
%A _R. H. Hardin_, Jan 06 2018