%I #4 Apr 02 2018 14:24:48
%S 1,2,4,10,28,84,260,816,2576,8152,25824,81840,259408,822304,2606720,
%T 8263456,26195776,83042752,263252544,834533120,2645541888,8386596224,
%U 26586234880,84280663296,267176990976,846974167552,2684981361664
%N Number of nX3 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero.
%C Column 3 of A302150.
%H R. H. Hardin, <a href="/A302146/b302146.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 4*a(n-1) -2*a(n-2) -2*a(n-3)
%e Some solutions for n=5
%e ..0..1..1. .0..1..1. .0..1..0. .0..1..0. .0..1..1. .0..1..1. .0..1..0
%e ..1..1..0. .1..1..0. .0..1..0. .0..1..0. .1..1..0. .1..1..0. .0..1..1
%e ..0..1..1. .1..1..1. .0..1..0. .0..1..1. .1..1..0. .0..1..0. .1..1..1
%e ..1..1..0. .1..1..1. .0..1..1. .1..1..0. .1..1..1. .0..1..0. .0..1..1
%e ..0..1..0. .1..1..0. .1..1..0. .0..1..0. .1..1..0. .0..1..0. .1..1..0
%Y Cf. A302150.
%K nonn
%O 1,2
%A _R. H. Hardin_, Apr 02 2018