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.
N(2 (-(1 - sqrt(41))^n + (1 + sqrt(41))^n))²/10)/(-(1 - sqrt(41))^(1 + n) + (1 + sqrt(41))^(1 + n))², for n=500
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random