# Pentagonal Number

## Pentagonal Number

Figurate number that we can represent by a set of points arranged on a regular convex pentagon or by a sequence partially superimposed over regular convex polygons.

The sequence of pentagonal numbers is: 1, 5, 12, 22, …, $$\dfrac{n\space ×\space (3n\space –\space 1)}{2}$$.