Factorial, the funny way

```
# lets count the permutations of [1..n]
def iterate(n):
    co = 0
    x = [0]
    while len(x) > 0:
        c = len(x) - 1
        x[c] += 1

        if x[c] <= n:
            if all(x[i] != x[c] for i in range(c)):
                if c < n - 1:
                    x.append(0)
                else:
                    co += 1
                    # print(co, x)
        else:
            x.pop()
    return co

print(iterate(5))
```