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 A286210 #6 Apr 05 2020 23:24:51 %S A286210 0,4,17,62,238,912,3468,13224,50655,194672,750165,2897898,11219322, %T A286210 43520672,169113746,658172740,2565143148,10010037116,39107620002, %U A286210 152948221004,598750691827,2346021879720,9199672561659,36102743330922 %N A286210 Number of n X 2 0..1 arrays with the number of 1's king-move adjacent to some 0 two less than the number of 0's adjacent to some 1. %C A286210 Column 2 of A286216. %H A286210 R. H. Hardin, <a href="/A286210/b286210.txt">Table of n, a(n) for n = 1..210</a> %e A286210 Some solutions for n=4 %e A286210 ..1..0. .0..1. .1..0. .0..0. .0..0. .0..0. .1..0. .0..1. .0..1. .0..0 %e A286210 ..0..0. .0..0. .0..1. .0..0. .0..1. .1..1. .1..0. .0..0. .0..1. .0..1 %e A286210 ..0..1. .0..1. .0..0. .0..0. .0..1. .0..0. .0..1. .1..0. .1..0. .0..1 %e A286210 ..0..1. .1..0. .0..1. .0..1. .1..0. .1..0. .0..0. .0..1. .0..0. .0..1 %Y A286210 Cf. A286216. %K A286210 nonn %O A286210 1,2 %A A286210 _R. H. Hardin_, May 04 2017