Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A hexagonal pyramidal number is a number formed by adding the first few hexagonal numbers. A figurate number is a number represented as a regular and discrete geometric pattern (e.g. dots) such as a polygonal number or a polyhedral number. The triangular numbers can be generalized in various ways. As used here, and in a number of other places, the term figurate number is meant to be broadly inclusive. In historical works about Greek mathematics the preferred term is figured number. For example A history of Greek Mathematics by T. Heath and Greek Mathematical Philosophy by E.A. Maziarz.