I've studied musical harmonics... a little. If the 1st harmonic is C4 (do4) then the 2nd harmonic is C5 (do5) which is found after 12 semitones along a pitch scale with audible frequencies in geometric progression until the double-frequency sound wave. I can calculate its common ratio:
The 3rd harmonic is G5 (sol5) which is found after 19 semitones towards the triple-frequency wave, so the ratio would be:
Are you sure that Music is based on Mathematics?