即求 ∑i=1n[∃a,b∈N+,i=ab]\sum_{i=1}^{n}{[\exists a,b \in N^+, i = a^b]}∑i=1n[∃a,b∈N+,i=ab] =1+∑p=p1a1p2a2p3a3...prar,r>1 or a1=1 and r=1nk(logqn−k+1)=1+\sum_{p = p_{1}^{a_1}p_{2}^{a_2}p_{3}^{a_3}...p_{r}^{a_r},r>1 \; or \; a1=1 \; and \; r=1}^{\sqrt[k]{n}}{(\log_qn-k+1)}=1+∑p=p1a1p2a2p3a3...prar,r>1ora1=1andr=1kn(logqn−k+1) 不知道对不对
