# 初探卡特兰数及有关问题

2021-11-25 18:34:41  阅读：18  来源： 互联网

### 二、卡特兰数的发现与定义

————百度百科

There are many, many combinatorial definitions of the Catalan numbers, but the most common might be that Cn counts the number of lattice paths from (0,0) to (n,n) that only take unit step right and up, and never cross the diagonal line y=x (but they are allowed to touch the diagonal line). There is not a unique definition of Catalan numbers because all of the various combinatorial definitions are equivalent to each other, so which one you take as your definition is a stylistic preference.

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————Math StackExchange论坛，源地址