Bode's law

Numerical sequence that gives the approximate distances, in astronomical units (distance between Earth and Sun = one astronomical unit), of the planets from the Sun by adding 4 to each term of the series 0, 3, 6, 12, 24, ... and then dividing by 10. Bode's law predicted the existence of a planet between Mars and Jupiter, which led to the discovery of the asteroid belt.

The ‘law’ breaks down for Neptune and the dwarf planet Pluto. The relationship was first noted in 1766 by the German mathematician Johann Titius, and developed by German astronomer Johann Bode.