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