Define a function:
$$f(x)=\sum_{k=0}^\infty \frac{1}{\bigg(\sum_{n=1}^{{2^k}}\frac{1}{n}\bigg)^x}=\sum_{k=0}^\infty \frac{1}{(H_{2^k})^x} $$
where $H_k$ is the k-th harmonic number.
Questions:
For what values of $x$ is $f$ convergent?
Can $f$ be analytically continued?
I think $f$ converges for $\Re(x)>1.$ And I think it can be analytically continued but may not have a nice closed form in terms of known functions.