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 A285147 #6 Apr 05 2020 23:10:26 %S A285147 1,14,113,786,5742,42176,314197,2359900,17852820,135811506,1037931930, %T A285147 7962744490,61286318733,473008466100,3659466705689,28371299519552, %U A285147 220366440810204,1714457590259554,13358188660727160,104218249427651818 %N A285147 Number of n X 3 0..1 arrays with the number of 1's horizontally or antidiagonally adjacent to some 0 one less than the number of 0's adjacent to some 1. %C A285147 Column 3 of A285152. %H A285147 R. H. Hardin, <a href="/A285147/b285147.txt">Table of n, a(n) for n = 1..210</a> %e A285147 Some solutions for n=4 %e A285147 ..1..0..0. .0..1..1. .0..0..0. .1..1..0. .1..1..1. .1..1..1. .0..1..0 %e A285147 ..0..0..1. .0..0..1. .1..0..1. .0..0..0. .1..1..0. .1..0..0. .1..1..1 %e A285147 ..0..0..0. .0..0..1. .0..1..0. .0..0..0. .0..0..0. .0..1..1. .0..0..0 %e A285147 ..1..1..0. .0..0..0. .1..0..0. .1..0..1. .1..0..1. .0..1..0. .1..0..0 %Y A285147 Cf. A285152. %K A285147 nonn %O A285147 1,2 %A A285147 _R. H. Hardin_, Apr 12 2017