serial

A work, such as a work of fiction, published in installments, often numbered and without a specified end.

A publication issued in successive parts, often numbered and with no predetermined end.

A serial number, esp. one required to activate software.

“Go to these sites for serials, cracks and keygens.”

To assign a serial number to (especially of aircraft)

Having to do with or arranged in a series.

“He was a serial entrepreneur, always coming up with a new way to make cash.”

Published or produced in installments.