Permutation de chiffres 1..n

from numpy import array

def fact(n):
    f = 1
    for i in range(2, n+1):
        f = f * i
    return f

n = 5
m = array([array([int()]*fact(n))]*n)
m[0, 0] = 1
for i in range(1, n):
    ne = fact(i)
    cnt = 0
    for j in range(ne):
        ch = str(m[i-1, j])
        for k in range(len(ch)+1):
            ch1 = ch[:k] + str(i+1) + ch[k:]
            m[i, cnt] = int(ch1)
            cnt += 1

for i in range(n):
    ne = fact(i + 1)
    print(m[i, :ne])