  We study transport through a Coulomb blockaded topologically nontrivial
superconducting wire (with Majorana end states) contacted by metallic leads. An
exact formula for the current through this interacting Majorana single-charge
transistor is derived in terms of wire spectral functions. A comprehensive
picture follows from three different approaches. We find Coulomb oscillations
with universal halving of the finite-temperature peak conductance under strong
blockade conditions, where the valley conductance mainly comes from elastic
cotunneling. The nonlinear conductance exhibits finite-voltage sidebands due to
anomalous tunneling involving Cooper pair splitting.
