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 A205159 #6 Jun 06 2018 15:19:06 %S A205159 143,447343,754700909,1427843505563,2654271236904226, %T A205159 4948963310952700521,9223088985799640757493, %U A205159 17190329064400885392195249,32039205913239024375598390394 %N A205159 Number of n X 6 0..3 arrays with no occurrence of three equal elements in a row horizontally, vertically or nw-to-se diagonally, and new values 0..3 introduced in row major order. %e A205159 Some solutions for n=5 %e A205159 ..0..0..1..0..1..1....0..1..0..1..0..0....0..1..1..2..1..1....0..0..1..0..2..0 %e A205159 ..2..0..2..2..1..0....0..1..1..2..3..2....0..2..0..3..0..0....0..0..1..1..0..1 %e A205159 ..3..2..2..0..2..3....3..0..1..2..1..1....2..1..1..0..2..1....3..3..2..2..3..1 %e A205159 ..3..0..1..2..3..3....2..1..2..3..0..1....0..1..0..2..2..1....3..0..2..0..2..2 %e A205159 ..0..1..1..2..3..0....2..0..0..1..3..0....0..3..1..0..1..0....0..0..1..0..3..3 %Y A205159 Column 6 of A205161. %K A205159 nonn %O A205159 1,1 %A A205159 _R. H. Hardin_, Jan 22 2012