In this example, we will learn us how to create a Fibonacci sequence with Python.

### Source Code

The Fibonacci sequence is defined as F (X) +F (X+1) =F (X+2).

```
#! /usr/bin/env python3
# -*- coding: utf-8 -*-
a = int(input("please input the first num in the sequence: "))
def FB(n):
if n==1 or n==2:
return int(a)
return FB(n-1)+FB(n-2)
print('Last number in Fibonacci Sequence:')
print(FB(10))
```

Output:

```
please input the first num in the sequence: 12
Last number in Fibonacci Sequence:
660
```