And trying to figure out what it's like moving on.
Summary
\[[n \mid k] = \frac{1}{n} \sum_{i = 0}^{n - 1} \omega^{ik}_{n}
\]
九个太阳
\[\begin{aligned}
&\sum_{i = 0}^{n} \binom{n}{i} \frac{1}{k} \sum_{j = 0}^{k - 1} \omega_{k}^{ij} \\
=&\frac{1}{k} \sum_{i = 0}^{n} \binom{n}{i} \sum_{j = 0}^{k - 1} (\omega_{k}^{j})^i \\
=&\frac{1}{k} \sum_{j = 0}^{k - 1} \sum_{i = 0}^{n} \binom{n}{i} (\omega_{k}^j)^i \\
=&\frac{1}{k} \sum_{j = 0}^{k - 1} (\omega_{k}^{j} + 1)^n
\end{aligned}
\]