According to Dalhousie mathematician Jason Brown, the chord used in the intro is actually a combination of guitar chords and... guess what? A piano.
Well I need to make this clear that I never realized this Beatle chord had been troublesome to millions of guitarists all over the world for 40 years until now.
Here are the facts:
The frequencies didn’t match the instruments on the song. Because George (Harrison) played a 12-string Rickenbacker, John played his 6 string, Paul had his bass and a 5th Beatle. Tadaaaa! Yep. George Martin, the band's manager played the piano on the record - the combination accounted for the "problematic" frequencies.
Brown figured out the chords. George Harrison played a2, a3, d3, d4, g3, g4, c4, and another c4 on the 12 string guitar. Paul McCartney played a d3 on his bass; producer George Martin was playing d3, f3, d5, g5, and e6 on the piano, while Lennon played a loud c5 on his six-string guitar.
Whatever this means.