---
# System prepended metadata

title: 階乗１から20

---

# 階乗１から20
```python=
def fact(number):
    result = 1
    for i in range(1,number+1):
        result *= i
    return result
A = []
for j in range(1,21):
    H=fact(j)
    A.append(H)
K = sum(A)
print(K)
```