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 A296535 #6 Apr 26 2020 21:01:20 %S A296535 1,3,16,126,2104,78660,5705431,820373528,239372827502,141301759543525, %T A296535 168080053760638246,403684916425998696873 %N A296535 Number of n X n 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 or 4 neighboring 1's. %C A296535 Diagonal of A296541. %e A296535 Some solutions for n=6 %e A296535 ..0..1..0..0..0..0. .0..0..0..1..0..0. .0..0..0..1..1..0. .0..1..1..1..1..0 %e A296535 ..1..1..0..1..1..0. .0..1..1..1..0..0. .0..0..1..0..1..0. .1..0..0..0..1..0 %e A296535 ..0..0..1..0..1..0. .0..1..0..0..0..0. .0..1..0..0..1..0. .1..1..1..1..0..0 %e A296535 ..0..1..0..0..1..0. .1..1..0..1..0..0. .0..1..0..0..1..1. .0..0..0..0..0..0 %e A296535 ..1..0..1..1..0..0. .0..0..1..1..0..0. .1..0..0..0..0..1. .0..0..0..0..0..0 %e A296535 ..1..1..0..0..0..0. .0..0..0..0..0..0. .1..1..1..1..1..0. .0..0..0..0..0..0 %Y A296535 Cf. A296541. %K A296535 nonn %O A296535 1,2 %A A296535 _R. H. Hardin_, Dec 15 2017