The nnn-th Catalan number is defined recursively as Cn=∑i=0n−1CiCn−1−iC_n = \sum_{i=0}^{n-1} C_i C_{n-1-i}Cn=∑i=0n−1CiCn−1−i with C0=1C_0 = 1C0=1. What is C4C_4C4?
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