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.
2\binom{n}{4}-\binom{n}{2}-n(\binom{n-2}{2}-(n-3))
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random