Which specific uniform numbers have not been retired by any of the

Titletown 101: Pack has retired just six uniform numbers - Star Journal

Lakers acknowledge error in Shaquille O'Neal's retired jersey - Los Angeles Times

The Pittsburgh Steelers list of unofficially retired numbers

Wayne Gretzky, Mario Lemieux and Others: The Best Retired Numbers in the NHL, News, Scores, Highlights, Stats, and Rumors

Retired number - Wikipedia

Best player who doesn't have their jersey retired for each NBA team

Rutgers retired jerseys: Who's already honored? Who's next?

Should the Celtics unretire numbers for current players to wear? - The Boston Globe

LeBron James will join this list of NBA players with numbers retired by multiple teams – NBC Los Angeles

Listing the only 3 NBA teams to not retire a single player's jersey