Fibonacci Numbers

A fibonacci number is a number that is equal to the sum of the previous two fibonacci numbers. As an example, the first 10 fibonacci numbers are

0, 1, 1, 2, 3, 5, 8, 13, 21, 34

Fibonacci numbers get very big, very quickly. The 100th fibonacci number is

354224848179262000000

The 1000th fibonacci number is.

4.346655768693743e+208