Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
\sum_{k=0}^{n-1}\dfrac{x^k}{k!}\sum_{L=0}^{\infty}\dfrac{(k+L)!}{L!}y^L
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random