Recurrence relations for the connection coefficients of orthogonal polynomials of a discrete variable

We give explicitly recurrence relations satisfied by the connection coefficients between two families of the classical orthogonal polynomials of a discrete variable (i.e., associated with the names of Charlier, Meixner, Krawtchouk and Hahn). Also, a recurrence relation is given for the coefficients in the formula expressing the nth associated polynomial in terms of the original polynomials.