Writing of factorial

CreatDate:2021.10.20

problem ：F(n)=1!+2!+3!+...+n!, Programming requirements F(50),F(100),F(1000) Value （n! Represents factorial operation ）

The first way to write it ：

n = int(input(' Input n Value : '))
res = 0
i = 1
j = 1
while n >= i:
    j *= i
    res += j
    i += 1
print(res)

 Input n Value : 2
3

The second way ：

math The library has ready-made functions ：factorial(n)

def func(n):
    from math import factorial as fact
    res = 0
    for i in range(1,n+1):
        res += fact(i)
    return res

func(50)

31035053229546199656252032972759319953190362094566672920420940313

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