2 Kings 16:1-20
In the seventeenth year of Pekah the son of Remaliah Ahaz the son of Jotham king of Judah began to reign.
Torrey's Topical Textbook—AKJV

2 Chronicles 28:1-27
Ahaz was twenty years old when he began to reign, and he reigned sixteen years in Jerusalem: but he did not that which was right in the sight of the LORD, like David his father:
Torrey's Topical Textbook—AKJV