Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsA Graph Theory Interpretation of the Sum of the First n Integershttp://demonstrations.wolfram.com/AGraphTheoryInterpretationOfTheSumOfTheFirstNIntegers/]]>http://demonstrations.wolfram.com/AGraphTheoryInterpretationOfTheSumOfTheFirstNIntegers/