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 A269142 #4 Feb 20 2016 06:20:53 %S A269142 8748,2727564,732561916,186315931804,45920055321732,11067174233536260, %T A269142 2621894498331024092,612729907775635265268,141617828339474744759764, %U A269142 32434464000726413874379876,7371987566769862222037312812 %N A269142 Number of nX7 0..3 arrays with some element plus some horizontally, antidiagonally or vertically adjacent neighbor totalling three no more than once. %C A269142 Column 7 of A269143. %H A269142 R. H. Hardin, <a href="/A269142/b269142.txt">Table of n, a(n) for n = 1..210</a> %e A269142 Some solutions for n=1 %e A269142 ..1..3..3..1..1..3..2. .2..3..3..2..2..2..1. .2..2..3..1..0..0..2 %Y A269142 Cf. A269143. %K A269142 nonn %O A269142 1,1 %A A269142 _R. H. Hardin_, Feb 20 2016