SOLUTION: What is the formula to sum the "n.n!" where ! means factorial and n is finite positive integer?

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Question 1184226: What is the formula to sum the "n.n!" where ! means factorial and n is finite positive integer?
Answer by ikleyn(52864) About Me  (Show Source):
You can put this solution on YOUR website!
.

The formula is


    1*1! + 2*2! + 3*3! + . . . + n*n! = (n+1)! - 1.


For the proof (quite easy) see this link


https://www.quora.com/What-is-the-sum-of-1-1-2-2-3-3-n-n