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 A303192 #4 Apr 19 2018 13:33:20 %S A303192 3,9,12,23,62,122,305,793,1757,4500,11625,27164,68288,174229,418787, %T A303192 1042345,2631836,6422387,15922406,39917606,98193097,243159537, %U A303192 606853585,1499009192,3711839149,9238182444,22867354964,56640304965,140740151139 %N A303192 Number of nX3 0..1 arrays with every element equal to 0, 1, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A303192 Column 3 of A303197. %H A303192 R. H. Hardin, <a href="/A303192/b303192.txt">Table of n, a(n) for n = 1..210</a> %F A303192 Empirical: a(n) = 2*a(n-1) -a(n-2) +11*a(n-3) -15*a(n-4) +6*a(n-5) -10*a(n-6) +6*a(n-7) for n>11 %e A303192 Some solutions for n=5 %e A303192 ..0..1..0. .0..1..0. .0..1..1. .0..1..1. .0..1..0. .0..1..0. .0..0..1 %e A303192 ..0..0..0. .1..1..0. .0..0..0. .0..0..0. .0..1..1. .0..1..0. .1..1..1 %e A303192 ..0..1..0. .0..1..0. .0..1..0. .0..1..0. .1..1..1. .0..0..0. .1..0..1 %e A303192 ..1..1..0. .0..1..0. .0..1..1. .0..1..0. .0..1..0. .0..1..0. .1..0..0 %e A303192 ..0..1..0. .0..1..0. .0..1..0. .0..1..0. .1..0..0. .0..1..0. .1..0..1 %Y A303192 Cf. A303197. %K A303192 nonn %O A303192 1,1 %A A303192 _R. H. Hardin_, Apr 19 2018