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.
PA com a_1 = 3 and r = 5 . Calcule a_(20) e
PA com a_1 = 3 and r = 5 . Calcule a_(20) e
Natural Language
Math Input
Extended Keyboard
