Description
In this assignment, you will write a program calculates [Tetranacci numbers](http://mathworld.wolfram.com/TetranacciNumber.html).
The formula for the `n`th Tetranacci number **T<sub>n</sub>** is defined as follows:
– T<sub>0</sub> = 0
– T<sub>1</sub> = 1
– T<sub>2</sub> = 1
– T<sub>3</sub> = 2
– T<sub>n</sub> = T<sub>n-1</sub> + T<sub>n-2</sub> + T<sub>n-3</sub> + T<sub>n-4</sub>
You need to complete following tasks:
1. Your task is to implement a recursive function `tetranacci` which accepts an integer `n` (you may assume that `n >= 0`), and computes the `n`-th Tetranacci number.
2. Print on the screen first 10 Tetranacci numbers.
