In Search of the Lost Chord

"Dr. Brown deduces that another George—George Martin, the Beatles producer—also played on the chord, adding a piano chord that included an F note impossible to play with the other notes on the guitar. The resulting chord was completely different than anything found in the literature about the song to date, which is one reason why Dr. Brown’s findings garnered international attention. He laughs that he may be the only mathematician ever to be published in Guitar Player magazine."

Ryan McNutt in a 2008 ScienceDaily article reports on efforts by a Canadian math professor to figure out the beginning to the Beatles' "A Hard Day's Night."