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 A206613 #7 Jul 22 2025 19:32:47 %S A206613 14,1155,623933,1719525751,24021101375251,1738678950539792051 %N A206613 Number of (n+1)X(n+1) 0..2 arrays with every 2X3 or 3X2 subblock having no more than two equal edges, and new values 0..2 introduced in row major order. %C A206613 Diagonal of A206621 %e A206613 Some solutions for n=4 %e A206613 ..0..0..1..2..2....0..0..0..0..1....0..0..0..1..2....0..0..1..2..2 %e A206613 ..2..1..2..1..1....1..2..1..2..0....1..0..2..0..2....2..1..0..0..1 %e A206613 ..1..2..1..1..2....1..0..2..1..0....0..1..0..0..1....2..0..1..1..0 %e A206613 ..1..1..0..2..1....1..2..0..0..2....2..0..2..2..0....0..2..2..0..1 %e A206613 ..2..0..1..2..1....0..0..1..0..1....1..2..1..2..1....0..1..0..2..1 %K A206613 nonn %O A206613 1,1 %A A206613 _R. H. Hardin_ Feb 10 2012