“The sons of Gershom were Libni his son, Jahath his son, Zimmah his son, Joah his son, Iddo his son, Zerah his son, and Jeatherai his son.”
Here we have 8 generations of (1) Gershom via (2) Libni his son. There are at least 4 Gershom Levites with the name of (3) Jahath and (5) Joah, all mentioned in this book, while there are 2 other Gershom Levites with the name of (4) Zimmah. There are 6 people with the name of (6) Iddo, most of them not Levites in the biblical literature. (7) Zerah was the same name as Perez’s twin brother, the son of Judah. In fact there were 4 other biblical persons with the name of Zerah. On the other hand, this is the only mention of a (8) Jeatherai in all the biblical literature. Their official functional roles were laid out in Numbers, chapter 4.