Definition:Hexagonal Number

Definition
Hexagonal numbers are those denumerating a collection of objects which can be arranged in the form of a regular hexagon.

They can be denoted:
 * $H_1, H_2, H_3, \ldots$

Also known as
Hexagonal numbers are also known as hexagon numbers.

Or we can just say that a number is hexagonal.

Some sources denote the $n$th hexagonal number as $\map H n$ in preference to $H_n$.

Also see

 * Equivalence of Definitions of Hexagonal Number


 * Closed Form for Hexagonal Numbers: $H_n = n \paren {2 n - 1}$


 * Definition:Polygonal Number:
 * Definition:Triangular Number
 * Definition:Square Number
 * Definition:Pentagonal Number