Genesis 38:8-9

38:8 And Judah said unto Onan, Go in unto thy brother’s wife, and marry her, and raise up seed to thy brother. 38:9 And Onan knew that the seed should not be his; and it came to pass, when he went in unto his brother’s wife, that he spilled [it] on the ground, lest that he should give seed to his brother.

Genesis 46:12

46:12 And the sons of Judah; Er, and Onan, and Shelah, and Pharez, and Zerah: but Er and Onan died in the land of Canaan. And the sons of Pharez were Hezron and Hamul.

Numbers 26:19

26:19 The sons of Judah [were] Er and Onan: and Er and Onan died in the land of Canaan.