Definition:Heptagonal Pyramidal Number

Definition
Heptagonal pyramidal numbers are those denumerating a collection of objects which can be arranged in the form of a heptagonal pyramid.

The $n$th heptagonal pyramidal number $Q_n$ is defined as:
 * $\ds Q_n = \sum_{k \mathop = 1}^n H_k$

where $H_k$ is the $k$th heptagonal number.

Also see

 * Closed Form for Heptagonal Pyramidal Numbers


 * Definition:Pyramidal Number
 * Definition:Tetrahedral Number
 * Definition:Square Pyramidal Number
 * Definition:Pentagonal Pyramidal Number
 * Definition:Hexagonal Pyramidal Number