Absolute stability region
Stable region in red.

Coefficients

\begin{align} \begin{array}{c|ccccccccccccccccc} & & & & & & & & & & & & & & & & & \\ \frac{1}{4} & \frac{1}{4} & & & & & & & & & & & & & & & & \\ \frac{1}{2} & \frac{1}{4} & \frac{1}{4} & & & & & & & & & & & & & & & \\ \frac{3}{4} & \frac{1}{4} & \frac{1}{4} & \frac{1}{4} & & & & & & & & & & & & & & \\ 1 & \frac{1}{4} & \frac{1}{4} & \frac{1}{4} & \frac{1}{4} & & & & & & & & & & & & & \\ \frac{1}{4} & \frac{251}{2880} & \frac{323}{1440} & - \frac{11}{120} & \frac{53}{1440} & - \frac{19}{2880} & & & & & & & & & & & & \\ \frac{1}{2} & \frac{29}{360} & \frac{31}{90} & \frac{1}{15} & \frac{1}{90} & - \frac{1}{360} & & & & & & & & & & & & \\ \frac{3}{4} & \frac{27}{320} & \frac{51}{160} & \frac{9}{40} & \frac{21}{160} & - \frac{3}{320} & & & & & & & & & & & & \\ 1 & \frac{7}{90} & \frac{16}{45} & \frac{2}{15} & \frac{16}{45} & \frac{7}{90} & & & & & & & & & & & & \\ \frac{1}{4} & \frac{251}{2880} & & & & & \frac{323}{1440} & - \frac{11}{120} & \frac{53}{1440} & - \frac{19}{2880} & & & & & & & & \\ \frac{1}{2} & \frac{29}{360} & & & & & \frac{31}{90} & \frac{1}{15} & \frac{1}{90} & - \frac{1}{360} & & & & & & & & \\ \frac{3}{4} & \frac{27}{320} & & & & & \frac{51}{160} & \frac{9}{40} & \frac{21}{160} & - \frac{3}{320} & & & & & & & & \\ 1 & \frac{7}{90} & & & & & \frac{16}{45} & \frac{2}{15} & \frac{16}{45} & \frac{7}{90} & & & & & & & & \\ \frac{1}{4} & \frac{251}{2880} & & & & & & & & & \frac{323}{1440} & - \frac{11}{120} & \frac{53}{1440} & - \frac{19}{2880} & & & & \\ \frac{1}{2} & \frac{29}{360} & & & & & & & & & \frac{31}{90} & \frac{1}{15} & \frac{1}{90} & - \frac{1}{360} & & & & \\ \frac{3}{4} & \frac{27}{320} & & & & & & & & & \frac{51}{160} & \frac{9}{40} & \frac{21}{160} & - \frac{3}{320} & & & & \\ 1 & \frac{7}{90} & & & & & & & & & \frac{16}{45} & \frac{2}{15} & \frac{16}{45} & \frac{7}{90} & & & & \\ \hline & \frac{7}{90} & & & & & & & & & & & & & \frac{16}{45} & \frac{2}{15} & \frac{16}{45} & \frac{7}{90}\\ & \frac{7}{90} & & & & & & & & & \frac{16}{45} & \frac{2}{15} & \frac{16}{45} & \frac{7}{90} & & & & \end{array}\end{align}

Properties