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 A302207 #4 Apr 03 2018 11:58:21 %S A302207 1,11,16,47,147,386,1065,3063,8624,24219,68527,193946,547869,1548531, %T A302207 4380048,12385479,35018011,99025330,280031137,791849343,2239169200, %U A302207 6331964803,17905479095,50632882698,143179634869,404883140379 %N A302207 Number of nX3 0..1 arrays with every element equal to 0, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302207 Column 3 of A302212. %H A302207 R. H. Hardin, <a href="/A302207/b302207.txt">Table of n, a(n) for n = 1..210</a> %F A302207 Empirical: a(n) = 3*a(n-1) -2*a(n-2) +9*a(n-3) -13*a(n-4) +2*a(n-5) -12*a(n-6) +12*a(n-7) -16*a(n-9) %e A302207 Some solutions for n=5 %e A302207 ..0..0..0. .0..1..1. .0..1..1. .0..1..0. .0..0..1. .0..1..1. .0..0..0 %e A302207 ..1..0..1. .0..1..1. .1..1..0. .1..1..1. .0..0..1. .0..1..1. .1..0..1 %e A302207 ..1..0..0. .0..1..0. .0..1..0. .0..1..0. .0..0..1. .0..1..1. .1..0..0 %e A302207 ..0..0..1. .0..1..1. .1..1..0. .0..1..1. .1..0..1. .0..1..1. .0..0..1 %e A302207 ..0..0..1. .1..1..1. .1..1..1. .1..1..1. .0..0..0. .1..1..0. .1..0..0 %Y A302207 Cf. A302212. %K A302207 nonn %O A302207 1,2 %A A302207 _R. H. Hardin_, Apr 03 2018