Create a function that returns the nth catalan number.In combinatorial mathematics, the Catalan numbers form a sequence of natural numbers that occur in various counting problems, often involving recursively-defined objects. They are named after the Belgian mathematician Eugène Charles Catalan (1814–1894). For more info, check out the resource tab.
getCatalanNumber(0) ➞ 1
getCatalanNumber(6) ➞ 132
getCatalanNumber(8) ➞ 1430
Inputs are zero and positive integers.