LG 4464 [国家集训队]JZPKIL

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查看原题'" class='mdui-btn mdui-btn-raised mdui-ripple'>点击加载点击跳转$$\begin{aligned}&\quad\sum{i=1}^n \gcd(i,n)^x lcm(i,n)^y\&=\sum{i=1}^n \frac{in}{lcm(i,n)}^x lcm(i,n)^y\&=\sum{i=1}^n (in)^x lcm(i,n)^{y-x}\&=\sum{i=1}^n (in)^x \frac{in}{\gcd(i,n)}^{y-x}\&=\sum{i=1}^n (in)^y \gcd(i,n)^……