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 A177314 #6 Mar 02 2016 11:27:03 %S A177314 1,1,48620,227873431500,66341857216154520,10150867545062935511900 %N A177314 Number of permutations of 9 copies of 1..n with all adjacent differences <= 2 in absolute value. %C A177314 a(n) = (9n)!/362880^n for n<=3. %Y A177314 Cf. A172613. %K A177314 nonn %O A177314 0,3 %A A177314 _R. H. Hardin_, May 06 2010