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.
f[n]=4*f[n-1]+21*f[n-2], f[0]=3, f[1]=1
f[n]=4*f[n-1]+21*f[n-2], f[0]=3, f[1]=1
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random
