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 A286212 #6 Apr 05 2020 23:26:08 %S A286212 0,62,684,10056,141018,2053994,30004158,443275636,6591532114, %T A286212 98620717026,1483077002788,22402256622648,339716751362128, %U A286212 5169528508115318,78910865975553660,1207934007828690708,18537787151292561428 %N A286212 Number of n X 4 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 A286212 Column 4 of A286216. %H A286212 R. H. Hardin, <a href="/A286212/b286212.txt">Table of n, a(n) for n = 1..186</a> %e A286212 Some solutions for n=4 %e A286212 ..0..0..0..1. .1..0..1..0. .0..1..0..1. .1..0..0..0. .0..1..0..1 %e A286212 ..1..1..0..0. .1..0..0..0. .0..0..1..1. .1..0..1..0. .0..1..0..0 %e A286212 ..1..1..0..0. .0..0..1..0. .0..1..1..0. .0..0..0..1. .1..0..0..1 %e A286212 ..1..0..1..0. .1..1..1..0. .1..0..0..0. .1..1..0..1. .1..1..0..0 %Y A286212 Cf. A286216. %K A286212 nonn %O A286212 1,2 %A A286212 _R. H. Hardin_, May 04 2017