\[\operatorname{Gi}\left(0\right)=\tfrac{1}{2}\operatorname{Hi}\left(0\right)=%
\tfrac{1}{3}\operatorname{Bi}\left(0\right)={1\Big{/}\!\left(3^{7/6}\Gamma%
\left(\tfrac{2}{3}\right)\right)=0.20497\;55424\ldots,}\]