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.
(floor(sqrt(n)) - (sum ceiling((n/x)-floor(n/x)), x=1, x=floor(sqrt(n))))
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random