OpenJudge

9276:Connected Graph

总时间限制:
1000ms
内存限制:
131072kB
描述

An undirected graph is a set V of vertices and a set of E∈{V*V} edges.An undirected graph is connected if and only if for every pair (u,v) of vertices,u is reachable from v.

You are to write a program that tries to calculate the number of different connected undirected graph with n vertices.
For example,there are 4 different connected undirected graphs with 3 vertices.

输入

The input contains several test cases. Each test case contains an integer n, denoting the number of vertices. You may assume that 1<=n<=50. The last test case is followed by one zero.

输出

For each test case output the answer on a single line.

样例输入
1
2
3
4
0
样例输出
1
1
4
38
全局题号
9276
添加于
2016-06-16
提交次数
84
尝试人数
58
通过人数
30