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 A121107 #6 Oct 04 2012 10:28:58 %S A121107 68889,27648,2688,768,336,54,20,0 %N A121107 Trajectory of 68889 under "x -> product of digits of x" map. %C A121107 This is the smallest number of persistence 7 (cf. A003001). %H A121107 N. J. A. Sloane, <a href="http://neilsloane.com/doc/persistence.html">The persistence of a number</a>, J. Recreational Math., 6 (1973), 97-98. %Y A121107 Cf. A003001. %K A121107 nonn,fini,full,base %O A121107 1,1 %A A121107 _N. J. A. Sloane_, Aug 12 2006 %E A121107 Edited by _Charles R Greathouse IV_, Aug 06 2010