utils/scrapers/prescraped/codeforces/Problems/1957E

You are given an integer n. The function C(i,k) represents the number of distinct ways you can select k distinct numbers from the set {1,2,…,i} and arrange them in a circle†.Find the value of n∑i=1i∑j=1(C(i,j)modj). Here, the operation xmody denotes the remainder from dividing x by y.Since this value can be very large, find it modulo 109+7.† In a circular arrangement, sequences are considered identical if one can be rotated to match the other. For instance, [1,2,3] and [2,3,1] are equivalent in a circle.