```
class Solution(object):
def getPermutation(self, n, k):
"""
:type n: int
:type k: int
:rtype: str
"""
visited = [0 for i in range(n)]
fact = [math.factorial(n - i - 1) for i in range(n)]
ans = ""
k -= 1
for i in range(n):
t = k / fact[i]
for j in range(n):
if not visited[j]:
if t == 0:
break
t -= 1
ans += str(j + 1)
k %= fact[i]
visited[j] = 1
return ans
```