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 A275564 #4 Aug 01 2016 21:27:20 %S A275564 48,2592,3552,23712,138600,867456,5360184,33275880,206892990, %T A275564 1286374716,7998368250,49754459556,309431155980,1924683955344, %U A275564 11971565665080,74462297454048,463161757751784,2880875453047152,17919172630925406 %N A275564 Number of nX7 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 A275564 Column 7 of A275565. %H A275564 R. H. Hardin, <a href="/A275564/b275564.txt">Table of n, a(n) for n = 1..210</a> %e A275564 Some solutions for n=4 %e A275564 ..0..1..1..2..2..1..1. .0..0..1..1..0..0..2. .0..1..2..0..0..2..1 %e A275564 ..2..0..1..2..2..0..0. .0..0..2..2..0..0..2. .0..1..1..0..2..2..0 %e A275564 ..2..0..0..1..1..2..0. .1..1..2..2..1..1..0. .2..2..0..1..1..0..2 %e A275564 ..1..2..0..0..1..1..2. .1..1..0..0..2..2..1. .1..0..2..2..0..1..2 %Y A275564 Cf. A275565. %K A275564 nonn %O A275564 1,1 %A A275564 _R. H. Hardin_, Aug 01 2016