FYI--Bach Math
I found the following quote in the liner notes of Richard Elgar and the Academy of Ancient Music, recording, Bach Brandenburg Concertos (2009), Harmonia Mundi. "Mathematic games prevail in no. 3 for those wishing to discover them. These range from the simple use of the numbers 3 (3rd concerto, 3 violins, 3 violas, 3 celli, 3-note rhythmic patterns, 3 half-note periods of harmonic rhythm and 7 (the last movement reduces to 7 'parts', the melodic sixteenth-note 'wave' spans a seventh, etc.)" And there's even more Bach math written up in the liner notes.