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.
binom(2n,n)*1/(4^n*(2n+1)) for n = 3
binom(2n,n)*1/(4^n*(2n+1)) for n = 3
Natural Language
Math Input
Extended Keyboard