# Any known particularities/theorems about the serie 2^a_0 + 3*2^a_1 + ... + 3^n * 2^a_n? [closed]

Are there any known facts/particularities/theorems about structures as the one below?

$$3^0 \cdot 2^{a_0} +3^1 \cdot 2^{a_1} + ... + 3^n \cdot 2^{a_n}$$

$$n, a_0, a_1, .. a_n \in N$$