Question 68
When each cell in the table $1 \times n$ is colored with one of the colors $a_1, a_2, \dots, a_n$, find the number of distinct colorings such that cells numbered $i_1, i_2, \dots, i_k$ are colored differently and are colored only with colors $a_{i_1}, a_{i_2}, \dots, a_{i_k}$.