  Horizontal and vertical generating functions and recursion relations have
been investigated by Comtet for triangular double sequences. In this paper we
investigate the horizontal and vertical log-concavity of triangular sequences
assigned to polynomials which show up in combinatorics, number theory and
physics. This includes Laguerre polynomials, the Pochhammer polynomials, the
D'Arcais and Nekrasov--Okounkov polynomials.
