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 A284220 #6 Apr 05 2020 22:45:02 %S A284220 19,495,22729,1214427,68272108,3945536189,232036495984,13815034342734, %T A284220 830095968128023,50232637096543404,3057032671368258137, %U A284220 186904092471409961598,11471093132331725037674,706316591332466208589249 %N A284220 Number of n X 6 0..1 arrays with the number of 1's horizontally or antidiagonally adjacent to some 0 equal to the number of 0's adjacent to some 1, with top left element zero. %C A284220 Column 6 of A284222. %H A284220 R. H. Hardin, <a href="/A284220/b284220.txt">Table of n, a(n) for n = 1..144</a> %e A284220 Some solutions for n=3 %e A284220 ..0..1..1..0..0..1. .0..0..1..0..1..0. .0..0..0..0..1..0. .0..0..0..0..0..1 %e A284220 ..0..1..0..1..0..0. .0..0..1..1..1..1. .0..0..1..1..0..1. .0..0..0..1..0..1 %e A284220 ..1..1..1..0..1..1. .0..1..1..0..0..0. .0..1..0..1..0..1. .0..0..0..1..0..1 %Y A284220 Cf. A284222. %K A284220 nonn %O A284220 1,1 %A A284220 _R. H. Hardin_, Mar 23 2017