$\sum_{d = 1}^n\mu^2(d)d^{k + 1} \sum_{t = 1}^{\left\lfloor\frac{n}{d}\right\rfloor}\mu(t) \sum_{i = 1}^{\left\lfloor\frac{n}{td}\right\rfloor}\sum_{j = 1}^{\left\lfloor\frac{m}{td}\right\rfloor}(i + j)^k * (t^k)$

为什么最后会多一个 $t^k$ 呢？？？