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 A268910 #4 Feb 15 2016 15:04:43 %S A268910 0,159744,5038848,154472184,4513169016,129834259704,3679171151832, %T A268910 103095286509168,2860978283523432,78747017051741472, %U A268910 2152203067541169000,58462727175138511872,1579670961301113123600,42485047384554878027688 %N A268910 Number of 7Xn 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once. %C A268910 Row 7 of A268904. %H A268910 R. H. Hardin, <a href="/A268910/b268910.txt">Table of n, a(n) for n = 1..210</a> %H A268910 R. H. Hardin, <a href="/A268910/a268910.txt">Empirical recurrence of order 54</a> %F A268910 Empirical recurrence of order 54 (see link above) %e A268910 Some solutions for n=2 %e A268910 ..0..0. .1..1. .0..0. .1..0. .0..0. .2..0. .1..0. .1..0. .0..1. .1..0 %e A268910 ..1..0. .0..0. .0..1. .0..2. .0..2. .1..0. .1..0. .2..1. .2..1. .2..2 %e A268910 ..2..1. .1..2. .0..0. .1..2. .2..1. .1..0. .0..0. .2..1. .2..2. .2..2 %e A268910 ..2..1. .2..1. .1..2. .2..2. .2..2. .0..1. .2..1. .2..1. .2..2. .2..1 %e A268910 ..0..1. .0..0. .2..1. .2..1. .1..0. .0..0. .0..0. .0..1. .2..1. .2..1 %e A268910 ..0..1. .0..1. .2..2. .0..0. .1..0. .0..1. .1..0. .0..0. .2..1. .0..1 %e A268910 ..0..1. .2..2. .0..1. .0..1. .0..1. .0..0. .0..1. .0..0. .1..2. .2..2 %Y A268910 Cf. A268904. %K A268910 nonn %O A268910 1,2 %A A268910 _R. H. Hardin_, Feb 15 2016