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 A302883 #6 Sep 16 2020 19:00:23 %S A302883 1,2,37,238,20937,3452246,2899297652,7977498513759,75895729469717417 %N A302883 Number of n X n 0..1 arrays with every element equal to 0, 2, 3, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302883 Diagonal of A302889. %e A302883 Some solutions for n=5 %e A302883 ..0..1..1..0..1. .0..0..0..0..0. .0..0..1..1..1. .0..0..0..1..1 %e A302883 ..1..1..0..0..0. .0..0..0..0..0. .1..0..0..1..1. .1..0..0..1..1 %e A302883 ..0..0..1..0..0. .0..0..1..1..0. .1..0..0..0..0. .1..0..1..0..1 %e A302883 ..0..0..0..1..1. .1..1..1..0..0. .1..0..1..0..0. .0..0..0..1..1 %e A302883 ..1..0..0..1..1. .0..1..1..0..0. .0..0..0..0..0. .0..0..0..1..1 %Y A302883 Cf. A302889. %K A302883 nonn %O A302883 1,2 %A A302883 _R. H. Hardin_, Apr 15 2018