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Writing an expression in summation notation

  1. Jan 29, 2012 #1
    How would I write

    1 + n + n(n - 1) + n(n - 1)(n - 2) + ・・・ + n!

    in sigma notation? If it's possible.
     
  2. jcsd
  3. Jan 29, 2012 #2
    [tex]\sum_{i = 0}^{n} \frac{n!}{(n - i)!}[/tex]
     
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