rt,我记得洛谷有一道题求 ∑i=1n∑j=1n[gcd(i,j)=1]\sum^{n}_{i=1}\sum^{n}_{j=1}[\gcd(i,j)=1]∑i=1n∑j=1n[gcd(i,j)=1]的，求题号，谢谢
