%I #4 Apr 10 2018 19:06:53
%S 4,17,25,71,191,498,1321,3505,9240,24460,64759,171268,453200,1199361,
%T 3173346,8396961,22219739,58794851,155576745,411673594,1089327367,
%U 2882467725,7627305260,20182608868,53405199549,141315536296,373935069260
%N Number of nX3 0..1 arrays with every element equal to 0, 1, 2 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
%C Column 3 of A302623.
%H R. H. Hardin, <a href="/A302618/b302618.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) +a(n-2) +4*a(n-3) -4*a(n-4) -4*a(n-5) +a(n-6) -4*a(n-7) -4*a(n-9) for n>11
%e Some solutions for n=5
%e ..0..1..0. .0..1..1. .0..1..0. .0..1..1. .0..1..0. .0..1..1. .0..0..1
%e ..1..1..1. .0..1..0. .1..1..0. .1..0..0. .1..0..1. .0..0..1. .0..1..1
%e ..0..0..0. .1..1..0. .0..0..1. .1..0..1. .1..0..1. .1..0..1. .0..1..0
%e ..1..1..1. .1..0..0. .1..0..1. .1..0..0. .1..0..1. .1..0..1. .1..1..0
%e ..0..0..0. .1..0..1. .1..0..1. .1..1..0. .1..0..1. .0..0..1. .1..0..0
%Y Cf. A302623.
%K nonn
%O 1,1
%A _R. H. Hardin_, Apr 10 2018