*Based on this Numberphile video: https://www.youtube.com/watch?v=Wim9WJeDTHQ*
---
Multiply all the digits of a nonnegative integer `n` by each other, repeating with the product until a single digit is obtained. The number of steps required is known as the **multiplicative persistence**.
Create a function that calculates the individual results of each step, not including the original number, but including the single digit, and outputs the result as a list/array. If the input is a single digit, return an empty list/array.
## Examples
```
per(1)  = []
per(10) = [0]
// 1*0 = 0
per(69) = [54, 20, 0]
// 6*9 = 54 --> 5*4 = 20 --> 2*0 = 0
per(277777788888899) = [4996238671872, 438939648, 4478976, 338688, 27648, 2688, 768, 336, 54, 20, 0]
// 2*7*7*7*7*7*7*8*8*8*8*8*8*9*9 = 4996238671872 --> 4*9*9*6*2*3*8*6*7*1*8*7*2 = 4478976 --> ...
```
def per(n):
    if n<10:
        return []
    l=[]
    while n>9:
        total=1
        num=str(n)
        for i in num:
            total*=int(i)
        l.append(total)
        n=total
    return l

def per(n):
    if n<10:
        return []
    l=[]
    while n>9:
        total=1
        num=str(n)
        for i in num:
            total*=int(i)
        l.append(total)
        n=total
    return l
