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 A177629 #5 Mar 02 2016 11:01:15 %S A177629 1,1,20,1680,369600,167714730,136194434423,179979692293317, %T A177629 361532596882040400 %N A177629 Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, up, up, up, up. %Y A177629 Cf. A014606. %K A177629 nonn %O A177629 0,3 %A A177629 _R. H. Hardin_, May 10 2010