$\displaystyle \sum_{k=1}^\infty (\frac{2}{3})^{k+2}$

This is what I did.

$\displaystyle \sum_{k=1}^\infty \frac{4}{9}*(\frac{2}{3})^{k}$

$\displaystyle a=\frac{4}{9}, r=\frac{2}{3}<1$

Threfore series converges to

$\displaystyle \frac{4}{3}$

This seems correct to me. However when I try to solve it thorugh maple (software) it outputs the result of $\displaystyle \frac89$. Did I do something wrong?