39,916,799
http://www.wolframalpha.com/input/?i=sum+n*n!+for+n%3D1+to+10
Let n! = 1 x 2 x 3 x 4 x ... x n for integer n >_1. What could be the value of 1! +(2 x 2!) + (3 x 3!) + (4 x 4!) + ... (10 x 10!)?
1 answer
1 answer