The Catalan numbers are named after the Belgian mathematician Eugène Charles Catalan.
The sequence of numbers is calculated with the formula
The first numbers are
1,
1,
2,
5,
14,
42,
132,
429,
1430,
4862,
16796,
58786,
208012,
742900,
2674440,
9694845,
35357670,
129644790,
477638700,
1767263190,
6564120420,
24466267020,
91482563640,
343059613650,
1289904147324,
4861946401452,
18367353072152,
69533550916004,
263747951750360,
1002242216651368,
3814986502092304