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 A296321 #6 Apr 26 2020 20:59:27 %S A296321 1,3,11,61,853,20088,850404,72224019,11207386103,3245575984755, %T A296321 1784744625714267,1830394475306895557,3517200566091635085954, %U A296321 12698075318404649075573041,85871949097296276009847589332 %N A296321 Number of n X n 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 neighboring 1's. %C A296321 Diagonal of A296327. %e A296321 Some solutions for n=5 %e A296321 ..0..0..0..1..1. .0..0..0..0..0. .0..1..1..0..0. .0..0..0..1..1 %e A296321 ..0..0..1..0..1. .0..0..0..0..0. .1..0..1..0..0. .0..0..1..0..1 %e A296321 ..0..0..1..0..1. .0..1..1..0..0. .1..1..0..1..1. .0..0..1..1..0 %e A296321 ..0..1..0..0..1. .0..1..0..1..0. .0..0..0..1..0. .0..0..0..0..0 %e A296321 ..0..1..1..1..0. .0..0..1..1..0. .0..0..0..0..0. .0..0..0..0..0 %Y A296321 Cf. A296327. %K A296321 nonn %O A296321 1,2 %A A296321 _R. H. Hardin_, Dec 10 2017