polygon division problem | polygon slicing | polygon triangulation

The problem of finding in how many ways E_n a plane convex polygon of n sides can be divided into triangles by diagonals. Euler first proposed it to Christian Goldbach in 1751, and the solution is the Catalan number E_n = C_(n - 2).

Catalan number | Catalan's problem | polygon diagonal | regular polygon division by diagonals