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 A284192 #6 Apr 06 2020 00:32:54 %S A284192 1,4,43,5268,1488503,3083244672,18564422929880,573011303756296687, %T A284192 62959447148443427630088 %N A284192 Number of n X n 0..1 arrays with the number of 1's horizontally, antidiagonally or vertically adjacent to some 0 equal to the number of 0's adjacent to some 1, with top left element zero. %C A284192 Diagonal of A284199. %e A284192 Some solutions for n=4 %e A284192 ..0..0..0..1. .0..0..1..1. .0..1..1..1. .0..1..0..1. .0..1..1..0 %e A284192 ..0..0..1..1. .1..0..0..0. .0..0..0..0. .0..0..0..1. .0..1..0..1 %e A284192 ..1..0..0..0. .1..0..0..0. .1..0..1..1. .0..1..1..0. .1..0..1..0 %e A284192 ..1..1..0..1. .1..1..1..1. .0..1..1..1. .1..0..1..1. .1..0..0..1 %Y A284192 Cf. A284199. %K A284192 nonn %O A284192 1,2 %A A284192 _R. H. Hardin_, Mar 22 2017