t = sum_(i=1..5) g_i(t)^6,  g_i(t) = c_i0 + c_i1 t + ... (centre values to 22 digits; '*' = exact fixed value)
g_1:  c_10 = (0.67) + (0) i *;   c_11 = (0.6609292775523857474556) + (0.02244153015098318843799) i  ;   c_12 = (-0.2911911269815325935876) + (0.03356829234872263262325) i  
g_2:  c_20 = (-0.3154481561489171661935) + (-0.2172489536186659136898) i  ;   c_21 = (-0.27) + (-0.4) i *;   c_22 = (-0.2197051409062817900242) + (-0.5804936964210720203552) i  
g_3:  c_30 = (0.5729233881240349130622) + (0.3287659608797223983029) i  ;   c_31 = (-0.5798583185433347034914) + (-0.3514274929534009600029) i  ;   c_32 = (-0.4929729879809472666596) + (-0.3089854775880654702649) i  
g_4:  c_40 = (0.3529298442371786455294) + (0.2021016428801970498381) i  ;   c_41 = (0.4086706125347323972626) + (0.3039887873218017007126) i  ;   c_42 = (0.5639489350902485980985) + (-0.1202051865878325254166) i  
g_5:  c_50 = (-0.01756629447109761446063) + (-0.2070785156673720378409) i  ;   c_51 = (-0.05243902779073488305508) + (1.192736312978495504894) i  ;   c_52 = (-0.03690033255791860845854) + (0.4361369344442846071356) i  
homogeneous form: x*y^11 = sum_i G_i(x,y)^6,  G_i = sum_j c_ij x^j y^(2-j)
coefficients of sum g_i^k - t at the centre (exact, shown as floats):
  3.9e-61, 2.0e-60, 5.1e-60, 1.2e-60, 1.4e-59, 1.7e-59, 5.0e-60, 4.9e-59, 5.5e-59, 2.6e-59, 5.6e-60, 9.8e-61, 1.9e-61
