不需要递归：

def smallestSquare(n):
    x = 1
    while isSquare(int(str(n)+str(x))) == False:
        x += 1
    return int(str(n)+str(x))

如果给定某个数字'n'，您要寻找以'n'开头的最小完美suqare，下面是一个可行的方法：

import math

def find_smallest_perfect_square(start: int) -> int:
    while True:
        if int(math.sqrt(start)) != math.sqrt(start):
            start += 1
        else:
            return start
        
def find_concatenation(n: int) -> int:
    str_n = str(n)
    while True:
        val = find_smallest_perfect_square(n)
        if str(val).startswith(str_n):
            return val
        else:
            n = val + 1

测试：

for i in range(10):
    print (f'The smallest perfect square that begins with {i} is {find_concatenation(i)}')

# Result:
    # The smallest perfect square that begins with 0 is 0
    # The smallest perfect square that begins with 1 is 1
    # The smallest perfect square that begins with 2 is 25
    # The smallest perfect square that begins with 3 is 36
    # The smallest perfect square that begins with 4 is 4
    # The smallest perfect square that begins with 5 is 529
    # The smallest perfect square that begins with 6 is 64
    # The smallest perfect square that begins with 7 is 729
    # The smallest perfect square that begins with 8 is 81
    # The smallest perfect square that begins with 9 is 9

如果你要找的是“k的最小值”，当它与n连接时，会产生一个完美的平方--上面的方法不能保证给予你你想要的。如果这是你所需要的，请说明。