Generalized Pentagonal Number/Sequence

Sequence of Generalized Pentagonal Numbers

The sequence of generalized pentagonal numbers, for $n \in \Z_{\ge 0}$, begins:

$GP_n = 0, 1, 2, 5, 7, 12, 15, 22, 26, 35, 40, 51, 57, 70, 77, 92, 100, \ldots$

This sequence is A001318 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).