\[(-1)^{n}\mathop{\mathrm{i}^{n}\mathrm{erfc}}\left(z\right)+\mathop{\mathrm{i}^%
{n}\mathrm{erfc}}\left(-z\right)=\frac{i^{-n}}{2^{n-1}n!}H_{n}\left(iz\right).\]