The Music of the Spheres
There is a mysterious and beautiful correlation between music and mathematics. There are rhythms in mathematics and there is much mathematical order in music, for example. And either discipline can stimulate the other. Einstein, an accomplished violinist, credited music with providing the inspiration out of which blossomed his theory of relativity (no longer a theory, of course, but a well-established fact). There are many more such examples.
In fact the whole universe seems ultimately definable, and to a large extent explicable, through mathematics, from gravity to distances, to planetary orbits, to quantum mechanics. The equations of Einstein, such as the simple E=mc², explain profoundly much. Johannes Kepler, too (whose name graces the current exoplanet-discovering space telescope), keenly felt the symbiosis of music and math. In his 1619 book Harmonices Mundi, he attempted to explain the harmonies of the world, and he described how music could be pleasingly paired with the kinetic geometry of the solar system. Pythagoras taught that focusing on pure, mathematically precise tones could calm and illuminate the mind.
There is also much magical math hidden in the almost musical rhythms of good writing. The prime number three shows up over and over, for example. A protagonist in a story tries twice to resolve some central conflict only to be somehow thwarted, but on a third supreme attempt, wins through. Three also creates an effective and interesting character grouping. As in The Three Musketeers by Dumas. Or a love triangle in almost any romance story. Or a sweeping saga told as a trilogy. Or the standard three-act play (the Setup, the Conflict, and the Resolution).