@Earl-of-Trumps saidFour Horsemen of the Apocalypse
88 PIANO KEYS
4 = H of the A
1 F, 2 F, R F, B F
Okay, maybe not an "equation" but still a phrase with numbers in it.
Too far afield?
@Earl-of-Trumps saidFour Horsemen of the Apocalypse
88 PIANO KEYS
4 = H of the A