Riemann zeta zeros as arbitrary eigenvalues

(*start*)
Clear[n, k, nn];
s = 1;
nnn = 4;
a = N[Flatten[{Im[ZetaZero[1]],
     Differences[Im[ZetaZero[Range[nnn]]]]}]];
MatrixForm[
 Table[Table[(a[[n]])^(s/2)*(a[[k]])^(s/2), {k, 1, nnn}], {n, 1, nnn}]]
Table[Max[
  Eigenvalues[
   Table[Table[(a[[n]])^(s/2)*(a[[k]])^(s/2), {k, 1, nn}], {n, 1,
     nn}]]], {nn, 1, nnn}]
(*end*)