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this is the power series:

$$\sum_{i=0}^\infty n(n-1)^2 (n-2) z^n.$$

how can I find a generating function from it? I could use the third derivative but the $n-1$ is squared so I don't know what to do..

  • 7
    Is the summation index supposed to be an $n$?2011-11-20
  • 3
    Earth to Adam, come in please. 6 answers in 22 hours, and no word from you. Are the answers any good? Do you need more help?2011-11-21

7 Answers 7