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 A177312 #5 Mar 02 2016 11:23:56 %S A177312 1,1,12870,9465511770,99561092450391000,151158246783053570131500, %T A177312 91756879673807945288868127380 %N A177312 Number of permutations of 8 copies of 1..n with all adjacent differences <= 3 in absolute value. %C A177312 a(n) = (8n)!/40320^n for n<=4. %Y A177312 Cf. A172609. %K A177312 nonn %O A177312 0,3 %A A177312 _R. H. Hardin_, May 06 2010