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 A269286 #8 Jan 21 2019 10:07:04 %S A269286 756,164556,27788292,4204943820,598478857956,81907569617580, %T A269286 10908770041709316,1424067311317705740,183070424003703987492, %U A269286 23250470194285817181804,2923940806264087088770116 %N A269286 Number of n X 5 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three no more than once. %H A269286 R. H. Hardin, <a href="/A269286/b269286.txt">Table of n, a(n) for n = 1..210</a> %F A269286 Empirical: a(n) = 234*a(n-1) - 14277*a(n-2) + 68796*a(n-3) - 86436*a(n-4). %F A269286 Empirical g.f.: 252*x*(3 - 49*x + 300*x^2 - 636*x^3) / (1 - 117*x + 294*x^2)^2. - _Colin Barker_, Jan 21 2019 %e A269286 Some solutions for n=2: %e A269286 ..0..3..3..1..0. .2..2..0..0..1. .3..1..0..3..2. .0..1..0..1..2 %e A269286 ..2..2..0..1..3. .1..0..2..3..2. .3..1..3..2..3. .1..1..1..3..3 %Y A269286 Column 5 of A269289. %K A269286 nonn %O A269286 1,1 %A A269286 _R. H. Hardin_, Feb 21 2016