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 A286213 #6 Apr 05 2020 23:26:52 %S A286213 0,238,2128,141018,1656022,113258929,1569283128,97311031516, %T A286213 1540259241508,86480812173044,1526208889551285,78586854206474282, %U A286213 1517934653629840928,72607979076706778162,1512452308916246272882 %N A286213 Number of n X 5 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 A286213 Column 5 of A286216. %H A286213 R. H. Hardin, <a href="/A286213/b286213.txt">Table of n, a(n) for n = 1..89</a> %e A286213 Some solutions for n=4 %e A286213 ..0..0..1..0..0. .0..0..0..1..0. .0..1..1..0..1. .0..0..0..1..1 %e A286213 ..0..0..1..0..1. .0..1..0..0..0. .0..0..1..0..1. .0..1..1..1..1 %e A286213 ..0..0..0..0..1. .0..1..1..0..1. .0..0..0..1..0. .1..0..1..0..0 %e A286213 ..1..0..1..1..1. .1..1..1..0..1. .0..0..1..0..1. .0..0..1..0..0 %Y A286213 Cf. A286216. %K A286213 nonn %O A286213 1,2 %A A286213 _R. H. Hardin_, May 04 2017