在“2005年地方联考题”中有这样一题:对于集合N={1,2,…,n}及它的每一个非空子集,定义一个“交替和”如下:按照递减的次序重新排列该子集元素,然后从最大数开始交替地减、加后继的数,例如集合{1,2,4,6,9}的“交替和”是9-6+4-2+1=6,集合{5}的“交替和”为5,当集合N中的n=2时集 In the “2005 Joint Examination Questions”, there is such a question: for the set N = {1, 2, ..., n} and each of its non-empty subsets, define an “alternate sum” as follows: Rearrange in descending order The subset element, then subtracts and adds subsequent numbers starting from the largest number. For example, the “alternate sum” of the set {1, 2, 4, 6, 9} is 9-6+4-2+1=6. The “alternate sum” of the set {5} is 5, when n = 2 in the set N