How can I calculate this limit (according to the mentioned idea in my question)?

Question

Someone have idea how can I calculate this?
$$ \lim _{n \rightarrow \infty} 2*(2^n-1)\cdot (\frac{2}{3.23})^{n+3} $$

I try to find a function that is smaller than this function, and limits to infinity (because that I think that the limit of this function is $\infty$).

Answer 1

HINT:

For $n\ge 1$,

$$2(2^n-1)\ge 2^n$$