Pentagonal Number/Examples

Definition
The first few pentagonal numbers are as follows:

From the definition:
 * $P_0 = 0$


 * [[File:1stTriangleNumber.png]]

The first pentagonal number:
 * $P_1 = 1$


 * [[File:2ndPentagonalNumber.png]]

The second pentagonal number:
 * $P_2 = 1 + 4 = 5$


 * [[File:3rdPentagonalNumber.png]]

The third pentagonal number:
 * $P_3 = 1 + 4 + 7 = 12$