+A **triangular number** is a quantity that can form an equilateral triangle when arranged as points or objects. It is the sum of all [Natural number](/wiki/natural_number) up to a given integer, and an example of a [Figurate number](/wiki/figurate_number).
+## See also
+- [Square number](/wiki/square_number)
+- [Sequence](/wiki/sequence)
+- [Arithmetic progression](/wiki/arithmetic_progression)