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# Sum of permutations!

I just found that sum of $$n$$ permutations with $$i$$ equals $$e\Gamma(n+1, 1)$$. In other words,

$$P(n,0) + P(n,1) + P(n, 2) + .... P(n,n) = e\Gamma(n+1, 1)$$. [where $$\Gamma(x,y)$$ is the incomplete gamma function].

Can anyone give a proof of this?

Note by Kartik Sharma
1 year, 11 months ago

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Hi Kartik Sharma , see this or the solution to this question .

But if you aren't familiar with Gamma function , see the link I provided or see it here .

Hope I was useful !!! · 1 year, 11 months ago

Thanks, that was helpful. You are quite good, solves almost all the problems. · 1 year, 11 months ago

You are welcome. · 1 year, 11 months ago