'Forty one' in the Bible

And Rehoboam, the son of Solomon, was king in Judah. Rehoboam was forty-one years old when he became king, and he was king for seventeen years in Jerusalem, the town which the Lord had made his out of all the tribes of Israel, to put his name there; his mother's name was Naamah, an Ammonite woman.

And he was king for forty-one years in Jerusalem; his mother's name was Maacah, the daughter of Abishalom.