用递归的方法求 1+2+3+1+2+3+ …… +N+N 的值。请你编写代码

def sum_recursive(n): if n == 1: return 1 elif n <= 3: return n + sum_recursive(n-1) else: return sum_recursive(n-3) + sum_recursive(n-2) + sum_recursive(n-1) + n

n = int(input("请输入一个整数：")) print("1+2+3+1+2+3+...+N+N的值为：", sum_recursive(n))