$\begin{array}{1 1} 4,-8, 16........\; or - \large\frac{4}{3},-\frac{8}{3}, -\frac{16}{3}...... \\ 4,8, 16........\; or \large\frac{4}{3},\frac{8}{3}, \frac{16}{3}......\\4,-8, 16........\; or - \large\frac{4}{5},-\frac{8}{5}, -\frac{16}{5}...... \\ 4,8, 16........\; or \;\large\frac{4}{5},\frac{8}{5}, \frac{16}{5}......\end{array} $