t = sum_(i=1..6) g_i(t)^8,  g_i(t) = c_i0 + c_i1 t + ... (centre values to 25 digits; '*' = exact fixed value)
g_1:  c_10 = (0.72) + (0) i *;   c_11 = (0.6016715159146565975992066) + (-0.3797513187914597624916664) i  ;   c_12 = (0.03233594064115566186199052) + (0.4632702385912829262434382) i  
g_2:  c_20 = (0.2338611596331021461176642) + (0.6620318209905792904929971) i  ;   c_21 = (-0.3463807018821845397163374) + (-0.4508485858740110108319085) i  ;   c_22 = (-0.2565710342041763627545625) + (-0.1071695632190212906745348) i  
g_3:  c_30 = (0.3380519181668444393850858) + (0.580637469514522640329954) i  ;   c_31 = (0.4275573033573910545094394) + (0.2640718395622721706990285) i  ;   c_32 = (-0.2026110677637917909398315) + (0.552018742411419781223496) i  
g_4:  c_40 = (0.3267060160743030058788799) + (-0.4755153974242201836320153) i  ;   c_41 = (0.6750258885130344156502427) + (0.4614199454146875940420958) i  ;   c_42 = (0.4757534626257427421750916) + (-0.07236828957616592412432615) i  
g_5:  c_50 = (-0.1793403898126417550060752) + (-0.2033111807376199013537270) i  ;   c_51 = (0.7266074795734196817440586) + (-0.2116141001861328747477816) i  ;   c_52 = (0.5805689689045154118043822) + (-0.22237339124619522611527) i  
g_6:  c_60 = (0.0881246058250119780770749) + (0.07906637147539149544645385) i  ;   c_61 = (-0.05512769368028880986797103) + (-0.4544612182548650768523459) i  ;   c_62 = (0.009989116117801176691452456) + (-0.6521833384181466786039255) i  
homogeneous form: x*y^15 = sum_i G_i(x,y)^8,  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):
  3.5e-61, 5.8e-61, 3.2e-60, 7.3e-60, 9.5e-60, 2.0e-59, 2.7e-59, 2.4e-59, 2.8e-59, 2.8e-59, 2.3e-59, 2.2e-59, 1.9e-59, 1.3e-59, 6.0e-60, 1.7e-60, 2.3e-61
