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 A295912 #6 Apr 26 2020 20:54:55 %S A295912 2,6,39,467,10290,431844,33703065,4933593439,1353357158724, %T A295912 695062929397500,668849535352606829,1205528922118577365911 %N A295912 Number of n X n 0..1 arrays with each 1 adjacent to 0 or 3 king-move neighboring 1's. %C A295912 Diagonal of A295918. %e A295912 Some solutions for n=5 %e A295912 ..0..0..0..0..0. .1..0..0..0..0. .1..0..1..0..1. .0..0..0..0..0 %e A295912 ..0..1..0..0..0. .0..0..1..0..1. .0..0..0..0..0. .0..0..1..0..0 %e A295912 ..0..0..0..0..1. .0..0..0..0..0. .0..0..0..0..0. .1..0..0..0..1 %e A295912 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..1..1. .0..0..0..0..0 %e A295912 ..1..0..0..0..1. .0..0..1..0..0. .0..1..0..1..1. .0..0..0..0..0 %Y A295912 Cf. A295918. %K A295912 nonn %O A295912 1,1 %A A295912 _R. H. Hardin_, Nov 29 2017