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 A275569 #4 Aug 01 2016 21:31:32 %S A275569 24,3456,7200,15000,57600,221184,867456,3402054,13630806,54613734, %T A275569 221152134,895530534,3642889494,14818750854,60456102318,246642942006, %U A275569 1008264289032,4121735121504,16864876108080,69005901096600 %N A275569 Number of 6Xn 0..2 arrays with no element equal to any value at offset (-2,0) (-1,2) or (0,-2) and new values introduced in order 0..2. %C A275569 Row 6 of A275565. %H A275569 R. H. Hardin, <a href="/A275569/b275569.txt">Table of n, a(n) for n = 1..210</a> %e A275569 Some solutions for n=4 %e A275569 ..0..0..1..2. .0..1..1..0. .0..1..1..0. .0..1..1..0. .0..1..2..0 %e A275569 ..0..1..2..2. .0..2..2..1. .0..2..1..1. .2..2..0..1. .1..1..0..2 %e A275569 ..1..1..0..0. .1..0..0..1. .2..2..0..1. .1..0..2..1. .2..0..0..2 %e A275569 ..2..2..1..0. .2..0..0..2. .1..0..2..2. .0..0..1..2. .2..0..1..1 %e A275569 ..0..2..2..1. .2..1..1..0. .0..1..1..0. .2..1..0..0. .0..2..2..0 %e A275569 ..0..0..2..2. .0..2..2..1. .2..1..1..0. .1..1..0..0. .1..1..0..2 %Y A275569 Cf. A275565. %K A275569 nonn %O A275569 1,1 %A A275569 _R. H. Hardin_, Aug 01 2016