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 A299655 #6 Jun 15 2020 14:49:57 %S A299655 1,8,227,22087,7411398,8607101770,34546300829517,478911551660693464, %T A299655 22930235691929943217996 %N A299655 Number of n X n 0..1 arrays with every element equal to 0, 1, 2, 3, 4, 5 or 7 king-move adjacent elements, with upper left element zero. %C A299655 Diagonal of A299661. %e A299655 Some solutions for n=5 %e A299655 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0 %e A299655 ..0..1..0..1..0. .0..1..0..0..1. .0..0..0..0..0. .0..0..1..1..1 %e A299655 ..1..0..1..1..1. .0..1..1..1..1. .0..0..1..0..0. .1..1..1..1..0 %e A299655 ..0..0..0..1..1. .0..0..0..1..0. .1..1..1..0..1. .0..0..0..0..1 %e A299655 ..1..0..0..0..0. .1..0..1..0..1. .0..1..0..0..1. .0..1..0..0..0 %Y A299655 Cf. A299661. %K A299655 nonn %O A299655 1,2 %A A299655 _R. H. Hardin_, Feb 15 2018