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 A177296 #5 Jan 25 2016 15:48:18 %S A177296 1,1,20,1680,369600,168168000,137225088000,182509367040000, %T A177296 156952841101056000,96333779412718848000 %N A177296 Number of permutations of 3 copies of 1..n with all adjacent differences <= 6 in absolute value. %C A177296 a(n) = (3n)!/6^n for n<=7. %Y A177296 Cf. A014606. %K A177296 nonn %O A177296 0,3 %A A177296 _R. H. Hardin_, May 06 2010