## lucas_number
### Instructions
Complete the body of the **function** `lucas_number` .
```rust
pub fn lucas_number(n: u32) -> u32 {}
```
This function receives a number `n` and returns the `n` th number in the Lucas Numbers where the `n` th number is the sum of the previous two numbers in the series.
The Lucas Numbers start like this: 2, 1, 3, 4, 7, 11, 18, 29, 47, 76, 123, etc...
### Usage
Here is a possible test for your function:
```rust
use lucas_number::lucas_number;
fn main() {
println!("The element in the position {} in Lucas Numbres is {}", 2, lucas_number(2));
println!("The element in the position {} in Lucas Numbres is {}", 5, lucas_number(5));
println!("The element in the position {} in Lucas Numbres is {}", 10, lucas_number(10));
println!("The element in the position {} in Lucas Numbres is {}", 13, lucas_number(13));
}
```
And its output:
```console
$ cargo run
The element in the position 2 in Lucas Numbers is 3
The element in the position 5 in Lucas Numbers is 11
The element in the position 10 in Lucas Numbers is 123
The element in the position 13 in Lucas Numbers is 521
$
```
