Absolute stability region
Stable region in red.

Coefficients

\begin{align} \begin{array}{c|cccccc} & & & & & & \\ \frac{1}{4} & \frac{1}{4} & & & & & \\ \frac{1}{4} & \frac{1}{8} & \frac{1}{8} & & & & \\ \frac{1}{2} & & & \frac{1}{2} & & & \\ \frac{3}{4} & \frac{3}{16} & - \frac{3}{8} & \frac{3}{8} & \frac{9}{16} & & \\ 1 & - \frac{3}{7} & \frac{8}{7} & \frac{6}{7} & - \frac{12}{7} & \frac{8}{7} & \\ \hline & \frac{7}{90} & & \frac{16}{45} & \frac{2}{15} & \frac{16}{45} & \frac{7}{90} \end{array}\end{align}

Properties