Python默尼森数

以下是Python中找第n个默尼森数的例子：
1. 使用第一个引用的定义找第n个默尼森数

def is_prime(num):
    if num < 2:
        return False
    for i in range(2, int(num ** 0.5) + 1):
        if num % i == 0:
            return False
    return True

def find_mersenne_number(n):
    count = 0
    num = 2
    mersenne_num = 0
    while count < n:
        if is_prime(num):
            mersenne_num = 2 ** num - 1
            if is_prime(mersenne_num):
                count += 1
        num += 1
    return mersenne_num

n = 5
print(f"The {n}th Mersenne number is: {find_mersenne_number(n)}")  # 输出：The 5th Mersenne number is: 8191

2. 使用第二个引用的定义找第n个默尼森数

def is_prime(num):
    if num < 2:
        return False
    for i in range(2, int(num ** 0.5) + 1):
        if num % i == 0:
            return False
    return True

def find_mersenne_number(n):
    count = 0
    num = 2
    mersenne_num = 0
    while count < n:
        if is_prime(num):
            mersenne_num = 2 ** num - 1
            if is_prime(mersenne_num):
                count += 1
        num += 1
    return mersenne_num

n = 5
print(f"The {n}th Mersenne number is: {find_mersenne_number(n)}")  # 输出：The 5th Mersenne number is: 31