摘要
利用生成函数解决了从n个元素的集合中任意重复选取r个元素且这r个元素中含有不同元素的个数一定时,所构成的不同r-序列的方法数.
In this paper,let N be a set with elements of n different types. An r-sequence of N is an ordered arrangement of r of the elements of N. By the way of generating function,we got the formula of the number of r-sequence with r-s different elements.
出处
《数学理论与应用》
2005年第3期84-86,共3页
Mathematical Theory and Applications
