!! used as default html header if there is none in the selected theme. OEF 组合

# OEF 组合 --- 介绍 ---

### 组合数

n 是一个正整数使得 Cn=Cn.

= n1+n2+...+n ,

### 正负数

S 是由 个正整数和 个负整数构成的集合. 这 个整数的绝对值都是不同的素数.

### 直线上的三角形

• Description: 一组关于组合的数值练习. This is the main site of WIMS (WWW Interactive Multipurpose Server): interactive exercises, online calculators and plotters, mathematical recreation and games
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