Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsAn Exploration of the "6174 Problem" and Some Generalizationshttp://demonstrations.wolfram.com/AnExplorationOfThe6174ProblemAndSomeGeneralizations/]]>http://demonstrations.wolfram.com/AnExplorationOfThe6174ProblemAndSomeGeneralizations/