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 A177300 #5 Mar 02 2016 10:58:58 %S A177300 1,1,70,34650,63063000,42251309100,17268436078740,6595449547140990, %T A177300 2941134289344290882 %N A177300 Number of permutations of 4 copies of 1..n with all adjacent differences <= 3 in absolute value. %C A177300 a(n) = (4n)!/24^n for n<=4. %Y A177300 Cf. A014608. %K A177300 nonn %O A177300 0,3 %A A177300 _R. H. Hardin_, May 06 2010