#递归计算阶乘

def factorial(n):

    if n == 1:

        return 1

    return n*factorial(n-1)

result = factorial(6)

print('阶乘：',result)

#递归求和

def accumulation(n):

    if n == 0:

        return 0

    return n+accumulation(n-1)

print('累加：',accumulation(6))

#斐波那契数列

def fibonacci(n):

    if n == 0:

        return 0

    if n == 1:

        return 1

    return fibonacci(n-1)+fibonacci(n-2)

print('斐波那契数列：',fibonacci(9))