  A series of Ruddlesden-Popper nickelates, Nd$_{n+1}$Ni$_{n}$O$_{3n+1}$ (${n}$
= 1-5), have been stabilized in thin film form using reactive molecular-beam
epitaxy. High crystalline quality has been verified by X-ray diffraction and
scanning transmission electron microscopy. X-ray photoelectron spectroscopy
indicates the ${n}$-dependent valence states of nickel in these compounds.
Metal-insulator transitions show clear ${n}$ dependence for intermediate
members (${n}$ = 3-5), and the low-temperature resistivities of which show
logarithmic dependence, resembling the Kondo-scattering as observed in the
parent compounds of superconducting infinite-layer nickelates.
