z
                               (-1)  z!
For Zeta(2), using, 2 --------------------------,
                      (x + z + 1) (2 x + z + 1)!

    the 20^th term of the weighted-average with

                                                           2
                    binomial(z + 2 x, x) binomial(x + z, z)

                                      is

                      49365586550772596159972753724151403
                      -----------------------------------
                      30010677963135299147717486757414144

delta is, .196602052344824026694184235397579414276952038251815556880480831936\
    990171032666041591911279122035676

                                z!
For Zeta(3), using, ---------------------------,
                                              2
                    (2 x + z + 1)! (x + z + 1)

    the 20^th term of the weighted-average with

                                       2                   2
                   binomial(z + 2 x, x)  binomial(x + z, z)

                                      is

               33338907204591442108470222377672879064526073959663
               --------------------------------------------------
               27734882697283685349587539578392633767240897382400

delta is, .227589590139806920480721177679695405098747248642036216099203195813\
    703123105264502278262256148531495