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 A269281 #4 Feb 21 2016 09:01:44 %S A269281 0,2598156,938176344,279339197256,75556007986536,19356924219624936, %T A269281 4786284820998999528,1154228064358389881112,273210106596010141952520, %U A269281 63745055133289730721040968,14703244384392257014503473256 %N A269281 Number of 6Xn 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three exactly once. %C A269281 Row 6 of A269276. %H A269281 R. H. Hardin, <a href="/A269281/b269281.txt">Table of n, a(n) for n = 1..210</a> %H A269281 R. H. Hardin, <a href="/A269281/a269281.txt">Empirical recurrence of order 40</a> %F A269281 Empirical recurrence of order 40 (see link above) %e A269281 Some solutions for n=2 %e A269281 ..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0 %e A269281 ..2..0. .2..1. .0..2. .0..2. .0..1. .2..0. .0..0. .2..2. .2..1. .0..1 %e A269281 ..1..3. .0..2. .3..0. .1..1. .0..0. .1..1. .3..2. .0..0. .1..1. .0..2 %e A269281 ..2..3. .0..0. .0..1. .0..0. .3..3. .3..1. .3..2. .3..1. .0..1. .2..1 %e A269281 ..1..0. .2..0. .0..2. .1..0. .3..1. .1..2. .3..3. .3..1. .1..0. .0..2 %e A269281 ..1..2. .0..0. .0..2. .1..0. .0..1. .3..1. .3..2. .3..2. .2..3. .0..1 %Y A269281 Cf. A269276. %K A269281 nonn %O A269281 1,2 %A A269281 _R. H. Hardin_, Feb 21 2016