Answer: xlii

AnswerCrossword Clue
XLIIForty-two
XLIIOld-style "quarantadue"
XLIISuper Bowl at which Tom Petty performed
XLII42 in the Forum
XLIIVII x VI
XLIIOne year into Claudius's reign
XLII2008 Super Bowl number
XLIIForum 42
XLIICXXVI-III
XLIID - CDLVIII
XLII42, once