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 A179220 #2 Mar 31 2012 14:41:48 %S A179220 1,3,5,6,7,25,20,16,121,2209,5460,571,1136,154963892093 %N A179220 Iterative mapping: a(1)=1, a(n)=A095904(a(n-1)). %C A179220 a(15) is greater than 10^18. %H A179220 Will Nicholes, <a href="http://willnicholes.com/math/primesigmap.htm">Iterative mapping of prime signatures</a>. %Y A179220 Cf. A095904, A179219. %K A179220 nonn %O A179220 1,2 %A A179220 _Will Nicholes_, Jul 10 2010