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.
1+ \sum_{n=1}^{2018}\left(4^n)
1+ \sum_{n=1}^{2018}\left(4^n)
Natural Language
Math Input
Extended Keyboard