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 A067896 #5 Nov 21 2013 12:47:36 %S A067896 41,126,63,192,96,48,24,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12, %T A067896 6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3, %U A067896 12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3,12,6,3 %N A067896 Trajectory of 41 under map x -> x/2 if x even, x-> 3x+3 if x odd. %t A067896 NestList[If[EvenQ[#],#/2,3#+3]&,41,100] (* _Harvey P. Dale_, Mar 30 2011 *) %K A067896 nonn %O A067896 0,1 %A A067896 _Ernst Berg_, May 15 2003