On the harmonic continuation of the Riemann xi function

We generalize the harmonic continuation of the Riemann xi-function to the $n$-dimension case, to obtain the solution to the Dirichlet problem on ${\mathbb{R}}_{+}^{n+1}\mathrm{.}$ We also provide a new expansion for the harmonic continuation of the Riemann xi-function using an expansion given by R.J. Duffin.