For comments on the use of the forward-difference operator Δx, the
backward-difference operator ∇x, and the central-difference operator
δx, see §18.2(ii).
In (18.20.1) X and wx are as in Table 18.19.1.
For the Hahn polynomials pn(x)=Qn(x;α,β,N) and
For the Krawtchouk, Meixner, and Charlier polynomials, F(x) and
κn are as in Table 18.20.1.
For the definition of hypergeometric and generalized hypergeometric functions see §16.2.
(For symmetry properties of pn(x;a,b,a¯,b¯) with
respect to a, b, a¯, b¯ see
Andrews et al. (1999, Corollary 3.3.4).)