"I'm my own grandpa..."

Jehoshaphat's son is joram,
joram's son is ahaziah,
ahaziah's son is joash,
joash's son is amaziah,
amaziah's son is azariah,
azariah's son is jotham
- 1 Chron 3:11,12

But joram's son is uzziah,
and uzziah's son is jotham
- Matt 1:8,9