Thread: Sum of first n fibbonaci numbers

Hey, I was just wondering if there was an explicit expression for the sum of the first n fibbonaci numbers.

Originally Posted by Chris11

Hey, I was just wondering if there was an explicit expression for the sum of the first n fibbonaci numbers.

This can be shown by induction or by the explicit formula for the Fibonacci sequence.

Thanks.

Proof:





.
.
.



now add them... what you get?