$T(1) = 1 $ ,
$T(n) = 3T(\sqrt[3]{n}) + \log_{2}(\log_{2}n)$.
I tried to define $ n = 2^{k}$.
So, $T(2^k) = 3T(2^{\frac{k}{3}}) + \log_{2}k$
Then defin $S(k) = T(2^k)$
So ,$S(k) = 3S(\frac{k}{3}) + \log_{2}k$
And now im pretty stuck, Someone has an idea ? Thanks.