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what is the sum of following permutation series $nP0 + nP1 + nP2+\cdots+ nPn$ ?

I know that $nC0 + nC1 +\cdots + nCn = 2^n$, but not for permutation. Is there some standard result for this ?

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    what is the meaning/definition of $nPk$?2012-06-21
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    @Mercy: $n(n-1)(n-2)\cdots(n-k+1)$. The ordered combinations of $k$ elements from $n$ possibilities.2012-06-21
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    I don't think there is a closed form for that sum, but since $n(n-1)\cdots(n-k+1)=n!/(n-k)!$ you can at least write it as $n!\sum_{k=0}^n1/k!$2012-06-21
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    @Mercy That is what I have written in my answer. $$\sum_{k=0}^{n} \dfrac1{k!} = \dfrac{e \Gamma(n+1,1)}{n!}$$2012-06-21

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