Generating function identities for $\zeta(2n+2), \zeta(2n+3)$ via the WZ method

Using the WZ method we present simpler proofs of Koecher's, Leshchiner's and Bailey-Borwein-Bradley's identities for generating functions of the sequences $\{\zeta(2n+2)\}_{n\ge 0}, \{\zeta(2n+3)\}_{n\ge 0}.$ By the same method we give several new representations for these generating functions yielding faster convergent series for values of the Riemann zeta function.