From my memory of astronomy: yes, though the asteroid belt is in one of the places for a planet.

Let me check: yes, that’s right, for our solar system.

Note though that no one knows whether this “law” is the result of anything much other than someone looked for number patterns and found one.

It suggests though that the planets formed from an accretion disk by gravity.

That “law” seems to be too simple to predict gravitational interactions between multiple planets.