n = int(input()) num = 0 a = 3 b = 3 f = [a, b] for i in range(n-2): a, b = a+b, a f.append(a) print(f) nums = 0 for i in range(n-1, -1, -1): nums = (nums+f[i]) * 2 print(nums) 反向斐波那契数列