i think you are right.

来源: 于 2010-07-13 10:05:44 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

I have got the recursive functions as well as the direct functions in two specific cases: n=1 and n=m-1. I will post the result soon after checking correctness.

But the direct functions in general case have not been found yet.