Arrangements and Combinations · Catalan Numbers: Introduction
Lesson 9
Problem. Let \(C(n)\) denote the number of valid parentheses sequences with \(n\) opening and \(n\) closing parentheses. For example, \(C(3)=5\): \[\texttt{()()() ()(()) (())() (()()) ((()))}\ .\] What is \(C(7)\)?
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