English Dictionary

Catalan number

noun

In combinatorial mathematics, any of a sequence of natural numbers that occur in various counting problems, often involving recursively defined objects; the nᵗʰ Catalan number is equal to (2n choose n) over (n+1).

Catalan numbers are a sequence of natural numbers that occur in various counting problems in combinatorial mathematics.

意味（1）

In combinatorial mathematics, any of a sequence of natural numbers that occur in various counting problems, often involving recursively defined objects; the nᵗʰ Catalan number is equal to (2n choose n) over (n+1).

AMBIGUITY LEADS TO AN EXPONENTIAL NUMBER OF TREES

I saw the man with the telescope on the box in the car under the table ...

AMBIGUITY LEADS TO AN EXPONENTIAL NUMBER OF TREES I saw the man with the telescope on the box in the car under the table ... n prepositional phrases ⇒ (n + 1)’th catalan number