That formula doesn’t work Fred.
A 20 year old man dating a 13.5 year old girl? That’ll get ‘im 20.
It’s not a dating formula, it’s a marriage formula, so there are obviously lower limits.
http://www.rollingstone.com/music/news/;kw=[36885,164064]?RS_show_page=1
Jerry Seinfeld brought laughs to the event with a short routine, in which, tongue firmly in cheek, he questioned some of McCartney's lyrical intentions. “Take ‘When I Saw Her Standing There,’ “ Seinfeld said, quoting the famous line: “ ‘She was just 17/You know what I mean.’ I’m not sure I do know what you mean, Sir Paul,” Seinfeld said. “I think I know what you mean and I think there's a law enforcement agency in a couple of states in this country that might like you to come downtown and answer a few questions about what you mean.”