The Fibonacci Number

Create a function that, given a number, returns the corresponding value of that index in the Fibonacci series.

The Fibonacci Sequence is the series of numbers:

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

The next number is found by adding the two numbers before it:

• The 2 is found by adding the two numbers before it (1+1).
• The 3 is found by adding the two numbers before it (1+2).
• The 5 is (2+3), and so on!

Examples

fibonacci(3) ➞ 3

fibonacci(7) ➞ 21

fibonacci(12) ➞ 233

Notes

The first number in the sequence starts at 1 (not 0).