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 A302735 #6 Sep 16 2020 18:58:52 %S A302735 1,8,228,21625,6947036,7530280825,27552364197684,340198731046937302, %T A302735 14168448763536007733003 %N A302735 Number of n X n 0..1 arrays with every element equal to 0, 1, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302735 Diagonal of A302741. %e A302735 Some solutions for n=5 %e A302735 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0 %e A302735 ..0..1..0..0..0. .0..0..1..1..1. .0..1..0..0..0. .0..0..1..0..0 %e A302735 ..1..0..1..1..1. .1..0..0..1..0. .0..1..1..1..1. .1..1..0..0..1 %e A302735 ..0..1..1..0..0. .1..0..1..0..0. .1..0..0..0..0. .1..1..0..0..1 %e A302735 ..1..0..0..1..1. .1..1..1..0..1. .0..1..0..1..0. .1..0..0..0..1 %Y A302735 Cf. A302741. %K A302735 nonn %O A302735 1,2 %A A302735 _R. H. Hardin_, Apr 12 2018