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 A269212 #4 Feb 20 2016 11:28:16 %S A269212 1620,360960,70371048,11985002256,1910809190712,292321215814512, %T A269212 43468685827935816,6331185189881558208,907653167033915932536, %U A269212 128509758210816109187040,18012346515317443065043752 %N A269212 Number of nX6 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three exactly once. %C A269212 Column 6 of A269214. %H A269212 R. H. Hardin, <a href="/A269212/b269212.txt">Table of n, a(n) for n = 1..210</a> %H A269212 R. H. Hardin, <a href="/A269212/a269212.txt">Empirical recurrence of order 42</a> %F A269212 Empirical recurrence of order 42 (see link above) %e A269212 Some solutions for n=2 %e A269212 ..0..2..2..3..2..3. .0..1..0..2..2..3. .0..0..2..2..3..2. .0..1..1..3..3..2 %e A269212 ..0..2..0..2..3..3. .0..1..3..3..2..3. .0..2..0..2..0..0. .0..1..3..2..2..3 %Y A269212 Cf. A269214. %K A269212 nonn %O A269212 1,1 %A A269212 _R. H. Hardin_, Feb 20 2016