Numbers 3:46

3:46 And for the redemption of the 273 firstborn males of the Israelites who exceed the number of the Levites,

Numbers 3:48-49

3:48 And give the money for the redemption of the excess number of them to Aaron and his sons.”

3:49 So Moses took the redemption money from those who were in excess of those redeemed by the Levites.