  Using recently developed methods, we perform high-accuracy calculations of
the susceptibility near beta_c for the D=3 version of Dyson's hierarchical
model. Using linear fits, we estimate the leading gamma and subleading Delta
exponents. Independent estimates are obtained by calculating the first two
eigenvalues of the linearized renormalization group transformation. We found
gamma = 1.29914073 (with an estimated error of 10^{-8}) and, Delta=0.4259469
(with an estimated error of 10^{-7}) independently of the choice of local
integration measure (Ising or Landau-Ginzburg). After a suitable rescaling, the
approximate fixed points for a large class of local measure coincide accurately
with a fixed point constructed by Koch and Wittwer.
