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 A303619 #4 Apr 27 2018 09:52:07 %S A303619 1,12,38,148,616,2520,10288,42100,172268,704776,2883500,11797636, %T A303619 48268920,197487780,808003420,3305872824,13525678764,55339088836, %U A303619 226414867352,926355911364,3790101263196,15506855855704,63444895485516 %N A303619 Number of nX3 0..1 arrays with every element equal to 0, 2, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A303619 Column 3 of A303624. %H A303619 R. H. Hardin, <a href="/A303619/b303619.txt">Table of n, a(n) for n = 1..210</a> %F A303619 Empirical: a(n) = 5*a(n-1) -5*a(n-2) +8*a(n-3) -12*a(n-4) +4*a(n-5) -4*a(n-6) for n>8 %e A303619 Some solutions for n=5 %e A303619 ..0..1..1. .0..1..0. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..0..0 %e A303619 ..1..1..1. .1..1..1. .0..0..1. .0..1..1. .0..0..0. .0..0..0. .0..0..1 %e A303619 ..0..1..0. .0..1..1. .1..0..0. .1..1..1. .0..0..1. .1..0..0. .0..0..1 %e A303619 ..0..1..1. .1..1..1. .0..0..0. .1..1..0. .1..0..0. .0..0..0. .1..0..0 %e A303619 ..1..1..0. .1..1..1. .0..0..1. .1..1..1. .0..0..1. .1..0..1. .0..0..0 %Y A303619 Cf. A303624. %K A303619 nonn %O A303619 1,2 %A A303619 _R. H. Hardin_, Apr 27 2018