One is the Loneliest Number

Jr. Jr. (singing):  One is the loneliest number.  Two is almost the loneliest number.
I'm not sure where he got it.  It's possible he heard me singing, "One is the loneliest number that you'll ever do.  Two can be as bad as one.  It's the loneliest number since the number one."  I haven't sung that song often, though.