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 A301539 #4 Mar 23 2018 11:05:51 %S A301539 13,42,154,603,2417,10783,47791,215362,990403,4616134,21616069, %T A301539 101719485,480319135,2272163307,10763099175,51036985495,242162709431, %U A301539 1149466726275,5457682636775,25918135231397,123098181426713,584702778533156 %N A301539 Number of nX6 0..1 arrays with every element equal to 0, 1 or 3 horizontally or vertically adjacent elements, with upper left element zero. %C A301539 Column 6 of A301541. %H A301539 R. H. Hardin, <a href="/A301539/b301539.txt">Table of n, a(n) for n = 1..210</a> %e A301539 Some solutions for n=5 %e A301539 ..0..0..0..1..0..1. .0..0..0..1..0..1. .0..1..0..1..0..1. .0..0..1..0..0..1 %e A301539 ..1..0..1..0..1..0. .1..0..1..0..1..1. .1..0..0..0..1..0. .1..1..1..1..1..0 %e A301539 ..1..1..0..1..0..1. .0..1..0..1..0..1. .0..1..1..1..0..1. .0..1..0..1..0..1 %e A301539 ..1..0..1..0..1..1. .0..0..1..1..0..0. .1..0..1..0..1..0. .1..0..1..0..1..0 %e A301539 ..0..1..1..1..0..1. .0..1..0..1..0..1. .0..0..0..1..1..1. .0..1..0..0..0..1 %Y A301539 Cf. A301541. %K A301539 nonn %O A301539 1,1 %A A301539 _R. H. Hardin_, Mar 23 2018