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 A177306 #6 Mar 02 2016 11:17:08 %S A177306 1,1,924,17153136,2308743493056,71614356453896256, %T A177306 1097239851330486263400 %N A177306 Number of permutations of 6 copies of 1..n with all adjacent differences <= 3 in absolute value. %C A177306 a(n) = (6n)!/720^n for n<=4. %Y A177306 Cf. A248814. %K A177306 nonn %O A177306 0,3 %A A177306 _R. H. Hardin_, May 06 2010