Matter coupled F(4) supergravity and the AdS(6) /CFT5 correspondence

F(4) supergravity, the gauge theory of the exceptional six-dimensional Anti -de Sitter superalgebra, is coupled to an arbitrary number of vector multip lets whose scalar components parametrize the quaternionic manifold SO(4, n) /SO(4) x SO(n). By gauging the compact subgroup SU(2)(d) x G, where SU(2)(d ) is the diagonal subgroup of SO(4) similar or equal to SU(2)(L) x SU(2)(R) (theR-symmetry group of six-dimensional Poincare supergravity) and G is a compact group such that dim G = n, we compute the scalar potential which, b esides the gauge coupling constants, also depends in non-trivial way on the parameter m associated to a massive 2-form B-mu nu of the gravitational mu ltiplet. The potential admits an AdS background for g = 3m, as the pure F(4 )-supergravity. We compute the scalar squared masses (which are all negativ e) and retrieve the results dictated by AdS(6)/CFT5 correspondence from the conformal dimensions of boundary operators. The boundary F(4) superconform al fields are realized in terms of a singleton superfield (hypermultiplet) in harmonic superspace with ag manifold SU(2)/U(1) = S-2. We analize the sp ectrum of short representations in terms of superconformal primaries and pr edict general features of the K-K specrum of massive type-IIA supergravity compactified on warped AdS(6) x S-4.