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 A205308 #6 Jun 06 2018 15:40:15 %S A205308 143,447343,996536552,2404472055439,5705396521337690, %T A205308 13585407518869992739,32325164995795813807941, %U A205308 76926439840751174108312233,183061289081893168962560628406 %N A205308 Number of n X 6 0..3 arrays with no occurrence of three equal elements in a row horizontally or vertically, and new values 0..3 introduced in row major order. %e A205308 Some solutions for n=5 %e A205308 ..0..0..1..2..3..3....0..0..1..0..0..1....0..0..1..0..0..2....0..0..1..2..0..2 %e A205308 ..2..3..0..0..1..2....1..2..1..0..1..3....1..3..2..2..3..2....2..1..1..0..1..1 %e A205308 ..3..2..2..0..2..1....1..3..3..1..1..3....3..2..2..3..1..1....2..2..3..0..0..3 %e A205308 ..0..1..2..1..3..2....0..1..0..0..2..0....2..1..1..2..1..3....0..0..1..1..2..3 %e A205308 ..1..3..0..3..1..0....0..1..1..3..3..0....2..3..1..0..0..1....3..3..2..0..0..2 %Y A205308 Column 6 of A205310. %K A205308 nonn %O A205308 1,1 %A A205308 _R. H. Hardin_, Jan 25 2012