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 A303191 #6 Sep 16 2020 19:03:41 %S A303191 1,3,12,46,523,8250,164295,6303961,332058205,27569938407, %T A303191 3963913990343,828978948856945 %N A303191 Number of n X n 0..1 arrays with every element equal to 0, 1, 3, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A303191 Diagonal of A303197. %e A303191 Some solutions for n=5 %e A303191 ..0..1..0..1..0. .0..1..1..1..0. .0..1..0..0..1. .0..1..0..1..0 %e A303191 ..0..0..1..1..0. .0..1..0..0..0. .1..1..0..1..0. .0..1..0..1..1 %e A303191 ..0..1..0..1..0. .0..1..0..1..0. .0..1..0..1..0. .1..1..0..1..0 %e A303191 ..0..1..0..1..0. .1..1..0..1..0. .1..0..1..1..0. .0..1..0..0..0 %e A303191 ..0..1..1..0..0. .0..1..0..1..0. .1..0..0..0..0. .0..1..0..1..0 %Y A303191 Cf. A303197. %K A303191 nonn %O A303191 1,2 %A A303191 _R. H. Hardin_, Apr 19 2018