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 A284160 #6 Apr 05 2020 22:32:56 %S A284160 3,13,62,461,2872,21790,154108,1174235,8682209,66280564,500956582, %T A284160 3842195970,29399659661,226595079490,1747037865422,13523344571285, %U A284160 104799855374221,814166845363267,6333123661559589,49348005883512820 %N A284160 Number of n X 3 0..1 arrays with the number of 1's horizontally or vertically adjacent to some 0 equal to the number of 0's adjacent to some 1, with top left element zero. %C A284160 Column 3 of A284165. %H A284160 R. H. Hardin, <a href="/A284160/b284160.txt">Table of n, a(n) for n = 1..210</a> %e A284160 Some solutions for n=4 %e A284160 ..0..0..0. .0..1..1. .0..1..1. .0..0..1. .0..0..1. .0..0..1. .0..0..1 %e A284160 ..1..0..0. .1..1..1. .1..0..1. .1..1..1. .1..0..0. .1..0..0. .0..1..1 %e A284160 ..0..1..1. .0..1..0. .0..1..0. .1..0..0. .1..1..1. .0..1..1. .0..0..1 %e A284160 ..1..1..1. .0..1..0. .0..0..1. .0..1..0. .0..1..0. .1..0..1. .1..0..1 %Y A284160 Cf. A284165. %K A284160 nonn %O A284160 1,1 %A A284160 _R. H. Hardin_, Mar 21 2017