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 A284329 #6 Apr 05 2020 22:51:24 %S A284329 3,13,49,415,2243,19385,122495,1021999,7013557,56860451,409700413, %T A284329 3264497171,24241023451,191315053703,1447951944431,11372354830403, %U A284329 87138438742684,682980793270605,5276292595391119,41334416149705333 %N A284329 Number of n X 3 0..1 arrays with the number of 1's horizontally, diagonally or antidiagonally adjacent to some 0 equal to the number of 0's adjacent to some 1, with top left element zero. %C A284329 Column 3 of A284334. %H A284329 R. H. Hardin, <a href="/A284329/b284329.txt">Table of n, a(n) for n = 1..210</a> %e A284329 Some solutions for n=4 %e A284329 ..0..1..1. .0..0..0. .0..1..0. .0..0..1. .0..1..1. .0..1..1. .0..0..1 %e A284329 ..1..0..0. .0..0..1. .0..1..1. .0..0..1. .1..1..1. .0..1..1. .0..1..0 %e A284329 ..1..1..0. .1..1..0. .1..0..0. .1..0..1. .0..1..0. .0..1..1. .0..0..1 %e A284329 ..1..0..0. .1..1..1. .1..0..1. .0..1..0. .1..1..0. .1..1..0. .1..1..1 %Y A284329 Cf. A284334. %K A284329 nonn %O A284329 1,1 %A A284329 _R. H. Hardin_, Mar 25 2017