Exponential-Golomb coding
An exponential-Golomb code (or just Exp-Golomb code) is a type of universal code. To encode any nonnegative integer x using the exp-Golomb code: Write down x+1 in binary Count the bits written, subtract one, and write that number of starting zero bits preceding the previous bit string.
Source: Wikipedia — Exponential-Golomb coding (CC BY-SA 4.0)