CodeForces 900D-Unusual Sequences(快速幂，莫比乌斯反演)CodeForces 900D-Unusual Sequences
CodeForces 900D-Unusual Sequences题目原址[http://codeforces.com/problemset/problem/900/D]题意有这样的序列 a1,a2,a3⋅⋅⋅ana_{1},a_{2},a_{3}···a_{n}a1,a2,a3⋅⋅⋅an 使得他们的和为 yyy ，最大公因数为 xxx，问满足这样的序列有多少个。题解练习题里的...
