pub fn double_factorial(n: usize) -> usize {
    let mut s = 1usize;
    let mut n = n;
    while n >= 2 {
        s *= n;
        n -= 2;
    }
    s
}
Double Factorial

# Type
: `usize -> usize`

# Usage

```
extern crate peroxide;
use peroxide::fuga::*;

assert_eq!(double_factorial(7), 105);
```
src/statistics/ops.rs