# Triangular Numbers |  | A triangular number or triangle number counts objects arranged in an equilateral triangle. **Triangular Numbers** are a type of figurate number, other examples being square numbers and cube numbers. The nth triangular number is the number of dots in the triangular arrangement with n dots on each side, and is equal to the sum of the n natural numbers from 1 to n. The sequence of triangular numbers, starting with the 0th triangular number, is | |-|-| | | wikipedia:: [Triangular number](https://en.wikipedia.org/wiki/Triangular_number) |