Charles Ellicott Commentary Genesis 46:15

"These are the sons of Leah, whom she bare unto Jacob in Paddan-aram, with his daughter Dinah: all the souls of his sons and his daughters were thirty and three." — Genesis 46:15 (ASV)

All the souls ... were thirty and three. That is: six sons, twenty-three grandsons, two great-grandsons, Dinah, and Jacob. Daughters and granddaughters are not counted.