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 A089420 #5 Mar 31 2012 14:02:17 %S A089420 1,1,2,4,4,1716,79560,214741800,19672368075360 %N A089420 Least common multiple of all cycle sizes in range [A014137(n-1)..A014138(n-1)] of permutation A082333/A082334. %H A089420 A. Karttunen, <a href="/A089408/a089408.c.txt">C-program for computing the initial terms of this sequence</a> %K A089420 nonn %O A089420 0,3 %A A089420 _Antti Karttunen_, Nov 29 2003