Numbers 26:5

Now these are the names of the sons of Israel—of Jacob and his sons—who were coming to Egypt: Reuben, Jacob’s firstborn.

These are the heads of their fathers’ households. The sons of Reuben, Israel’s firstborn: Hanoch and Pallu, Hezron and Carmi; these are the families of Reuben.

Now the sons of Reuben, Israel’s firstborn, their genealogical registration by their families, by their fathers’ households, according to the number of names, head by head, every male from twenty years old and upward, whoever was able to go out to war,

the sons of Reuben the firstborn of Israel were Hanoch and Pallu, Hezron and Carmi.