Absolute stability region
Stable region in red.

Coefficients

\begin{align} \begin{array}{c|cccc} & \frac{1}{12} & - \frac{\sqrt{5}}{12} & \frac{\sqrt{5}}{12} & - \frac{1}{12}\\ - \frac{\sqrt{5}}{10} + \frac{1}{2} & \frac{1}{12} & \frac{1}{4} & - \frac{7 \sqrt{5}}{60} + \frac{1}{6} & \frac{\sqrt{5}}{60}\\ \frac{\sqrt{5}}{10} + \frac{1}{2} & \frac{1}{12} & \frac{1}{6} + \frac{7 \sqrt{5}}{60} & \frac{1}{4} & - \frac{\sqrt{5}}{60}\\ 1 & \frac{1}{12} & \frac{5}{12} & \frac{5}{12} & \frac{1}{12}\\ \hline & \frac{1}{12} & \frac{5}{12} & \frac{5}{12} & \frac{1}{12} \end{array}\end{align}

Properties