'Forty one' in the Bible

Rehoboam the son of Solomon reigned in Judah. Rehoboam was forty-one years old when he began to reign, and he reigned seventeen years in Jerusalem, the city which the LORD had chosen out of all the tribes of Israel, to put his name there: and his mother's name was Naamah the Ammonitess.

He reigned forty-one years in Jerusalem: and his mother's name was Maacah the daughter of Abishalom.