$\displaystyle 2^{ \frac{1}{6} }$\displaystyle 2^{ \frac{1}{6} }

$\displaystyle 2^{ \frac{1}{5} }$\displaystyle 2^{ \frac{1}{5} }

$\displaystyle 2^{ \frac{1}{3} }$\displaystyle 2^{ \frac{1}{3} }

$\displaystyle 2^{ \frac{2}{3} }$\displaystyle 2^{ \frac{2}{3} }