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 A276253 #4 Aug 25 2016 11:07:56 %S A276253 365,9216,23000,188696,2003694,18671229,219977330,2410124377, %T A276253 24361263053,272372552980,2985497491633,31231199543135, %U A276253 341233988414188,3723139799743418,39589701942441676,428949119346736027 %N A276253 Number of 7Xn 0..2 arrays with no element equal to any value at offset (-2,-1) (-1,1) or (0,-2) and new values introduced in order 0..2. %C A276253 Row 7 of A276248. %H A276253 R. H. Hardin, <a href="/A276253/b276253.txt">Table of n, a(n) for n = 1..176</a> %e A276253 Some solutions for n=4 %e A276253 ..0..0..1..2. .0..1..1..0. .0..0..1..2. .0..0..1..1. .0..1..2..0 %e A276253 ..2..2..1..0. .0..0..1..2. .2..0..0..2. .1..0..2..2. .0..0..2..1 %e A276253 ..1..2..2..0. .1..2..0..0. .2..1..1..0. .2..1..1..0. .1..1..0..0 %e A276253 ..0..0..1..2. .0..1..1..2. .2..0..1..1. .0..2..1..0. .0..2..1..0 %e A276253 ..1..2..0..0. .2..0..0..1. .1..0..2..2. .0..0..2..2. .0..0..2..1 %e A276253 ..0..1..2..2. .1..2..0..0. .2..1..1..0. .2..1..1..2. .1..1..0..0 %e A276253 ..0..0..1..2. .0..1..1..2. .0..2..2..0. .0..2..1..1. .0..2..2..1 %Y A276253 Cf. A276248. %K A276253 nonn %O A276253 1,1 %A A276253 _R. H. Hardin_, Aug 25 2016