：假设停在铁路调度站入口处的车厢序列的编号一次为1，2，3，…，n。设计一个程序，求出所有可能由此输出的长度为n的车厢序列。-: Suppose stopped at the railway station at the entrance to the train scheduling sequence number one for 1,2,3, ..., n. Design a procedure to derive all the possible length of the resulting output sequence of n compartments.