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 A177315 #6 Mar 02 2016 11:28:42 %S A177315 1,1,48620,227873431500,21452752266265320000, %T A177315 230729955958244519983206000 %N A177315 Number of permutations of 9 copies of 1..n with all adjacent differences <= 3 in absolute value. %C A177315 a(n) = (9n)!/362880^n for n<=4. %Y A177315 Cf. A172613. %K A177315 nonn %O A177315 0,3 %A A177315 _R. H. Hardin_, May 06 2010