[填空题]
A professor and five ox rvjc 1hxgb6sj1- m +;m8g5nkf hisejx8qh 5tq;p is: ru1( students attend a talk given in a lecture series. They have a row of(sji e8qx5 :th;qp1 ru 8 seats to themselves.
Find the number of ways the professor and his students can sit if
1. the professor and his students sit together.
2. the students decide to sit at least one seat apart from their professor.
