xi function zeros plot

(*start xi function*)cons = 10;
ww = 400;
div = 10;
real = 1/2;
Monitor[TableForm[zz = Table[Clear[t, b, n, k, nn, x];
     z = N[cons + w/div, 20];
     polynomial =
      Normal[Series[
        1/2 (real + x + z*N[I, 20])*((real + x + z*N[I, 20]) - 1)*
         Pi^(-(real + x + z*N[I, 20])/
            2) Gamma[(real + x + z*N[I, 20])/2]*
         Zeta[(real + x + z*N[I, 20])], {x, 0, 10}]];
     digits = 20;
     b = With[{nn = 20},
       CoefficientList[Series[1/polynomial, {x, 0, nn}], x]];
     nn = Length[b] - 1;
     x = z*I + N[b[[nn - 1]]/b[[nn]], digits], {w, 0, ww}]];, w]
g1 = ListLinePlot[Flatten[Im[zz]], DataRange -> {cons, cons + ww/div}]
g2 = ListLinePlot[Flatten[Re[zz]], DataRange -> {cons, cons + ww/div},
   PlotRange -> {-2, 2}]
zz
(*end*)