The 2019 ICPC Asia Yinchuan Regional Programming Contest/2019银川区域赛 D Easy Problem(莫比乌斯反演+欧拉降幂)
题意给你n,m,d,kn,m,d,kn,m,d,k计算下列式子∑i1=1m∑i2=1m∑i3=1m⋯∑in=1m[gcd(i1,i2,i3,⋯ ,in)==d](i1i2i3⋯in)k\sum_{i_1=1}^m\sum_{i_2=1}^m\sum_{i_3=1}^m\cdots\sum_{i_n=1}^m[gcd(i_1,i_2,i_3,\cdots,i_n)==d](i_1i_2i_3\cdo