'Forty one' in the Bible

Now Rehoboam the son of Solomon reigned in Judah. He was forty-one years old when he began to reign, and he reigned seventeen years in Jerusalem, the city which, from all of the tribes of Israel, Yahweh chose to place his name. And the name of his mother [was] Naamah the Ammonitess.

He reigned forty-one years in Jerusalem, and the name of his mother [was] Maacah the daughter of Abishalom.