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 A179221 #2 Mar 31 2012 14:41:48 %S A179221 0,2,3,6,8,25,21,24,343,195,486,5929,35568,1450800 %N A179221 Iterative mapping: a(1)=0, a(n)=A179216(a(n-1)). %C A179221 a(15) is greater than 10^7 and of the form (p^5)(q^4)rs where p, q, r and s are distinct primes. %H A179221 Will Nicholes, <a href="http://willnicholes.com/math/primesigmap.htm">Iterative mapping of prime signatures</a>. %Y A179221 Cf. A179216, A179222. %K A179221 nonn %O A179221 1,2 %A A179221 _Will Nicholes_, Jul 10 2010