This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A318338 #4 Aug 24 2018 11:01:39 %S A318338 4,10,20,36,76,160,344,748,1624,3544,7724,16856,36776,80252,175128, %T A318338 382168,833996,1819992,3971720,8667356,18914520,41276600,90076716, %U A318338 196571800,428972904,936135100,2042900376,4458162072,9728917388 %N A318338 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. %C A318338 Column 3 of A318343. %H A318338 R. H. Hardin, <a href="/A318338/b318338.txt">Table of n, a(n) for n = 1..210</a> %F A318338 Empirical: a(n) = 2*a(n-1) +2*a(n-2) -3*a(n-3) -2*a(n-4) +2*a(n-5) for n>6 %e A318338 Some solutions for n=5 %e A318338 ..0..1..1. .0..0..1. .0..0..0. .0..1..1. .0..1..1. .0..0..0. .0..0..0 %e A318338 ..1..1..1. .0..0..1. .0..0..0. .1..1..1. .1..1..1. .0..0..0. .0..0..0 %e A318338 ..0..0..0. .0..0..1. .0..0..0. .1..1..1. .0..0..0. .1..1..1. .0..0..0 %e A318338 ..0..0..1. .0..0..1. .1..1..1. .1..1..0. .0..0..0. .1..1..1. .1..1..1 %e A318338 ..0..1..1. .0..0..1. .1..1..0. .1..0..0. .0..0..0. .1..1..1. .1..1..1 %Y A318338 Cf. A318343. %K A318338 nonn %O A318338 1,1 %A A318338 _R. H. Hardin_, Aug 24 2018