Starting with polynomial:
P : t^6 - 15*t^4 + 45*t^2 - 15
Extension levels are: 6 9
-------------------------------------------------
Trying to find an order 9 Kronrod extension for:
P1 : t^6 - 15*t^4 + 45*t^2 - 15
Solvable: 1
-------------------------------------------------
Ending with final polynomial:
P : t^15 - 13845/191*t^13 + 360405/191*t^11 - 4272555/191*t^9 + 24327405/191*t^7 - 64538775/191*t^5 + 68923575/191*t^3 - 18129825/191*t
-------------------------------------------------
Computing nodes and weights
  current precision for roots: 53
  current precision for roots: 106
 current precision for weights: 53
Linear system for weights solvable: 1
  current precision for roots: 106
  current precision for roots: 212
 current precision for weights: 106
Linear system for weights solvable: 1
Sufficient bits for target precision reached
-------------------------------------------------
The nodes are:
| (-3.3242574335521189524 - 1.3435752215134177504e-138j)  +/-  (1.84e-60, 1.84e-60j)
| (-5.5533529315903281928 - 7.3476769926515033223e-140j)  +/-  (6.39e-61, 6.39e-61j)
| (-4.3418637687749014379 - 8.3973451344588609397e-140j)  +/-  (1.58e-60, 1.58e-60j)
| (3.3242574335521189524 - 7.7675442493744463693e-139j)  +/-  (1.84e-60, 1.84e-60j)
| (-1.8891758777537106755 - 1.3383268808043809623e-139j)  +/-  (6.86e-61, 6.86e-61j)
| (5.5533529315903281928 - 6.5468117212487400229e-144j)  +/-  (5.92e-61, 5.92e-61j)
| (4.3418637687749014379 - 1.9219997713757768875e-143j)  +/-  (1.66e-60, 1.66e-60j)
| (-0.61670659019259415219 + 4.6127994513018645299e-143j)  +/-  (1.38e-62, 1.38e-62j)
| (-2.4440098084964929991 - 9.0093739283239541599e-146j)  +/-  (1.42e-60, 1.42e-60j)
| (1.8891758777537106755 + 7.5762421814790196115e-149j)  +/-  (7.2e-61, 7.2e-61j)
| (1.3498952853218839149 + 5.935406206663338617e-167j)  +/-  (1.68e-61, 1.68e-61j)
| (0.61670659019259415219 - 1.1767186841322676356e-184j)  +/-  (1.38e-62, 1.38e-62j)
| (-2.6932953280615256552e-189 - 2.6932953280615256552e-189j)  +/-  (5.71e-188, 5.71e-188j)
| (-1.3498952853218839149 - 5.2603424376201672954e-192j)  +/-  (1.9e-61, 1.9e-61j)
| (2.4440098084964929991 - 2.3972914754779408247e-193j)  +/-  (1.56e-60, 1.56e-60j)
-------------------------------------------------
The weights are:
| (0.0015157553175112424267 - 5.4309078323177894372e-141j)  +/-  (6.34e-19, 6.86e-49j)
| (1.1106256598128842121e-07 + 1.4669129378134463512e-144j)  +/-  (1.88e-22, 2.03e-52j)
| (3.5076530695648974756e-05 - 1.3636042934636768752e-142j)  +/-  (9.02e-21, 9.75e-51j)
| (0.0015157553175112424267 + 2.9860607884026238648e-141j)  +/-  (2.04e-21, 2.2e-51j)
| (0.026005678400867750431 - 5.6133747518685074821e-140j)  +/-  (3.79e-18, 4.1e-48j)
| (1.1106256598128842121e-07 - 1.1116957287313014248e-144j)  +/-  (1.2e-24, 1.3e-54j)
| (3.5076530695648974756e-05 + 8.3633570112196314766e-143j)  +/-  (3.73e-23, 4.04e-53j)
| (0.23036016700500592493 - 5.4870689259491954197e-140j)  +/-  (3.42e-19, 4.01e-49j)
| (0.015614589894054148587 + 2.2816940522606626224e-140j)  +/-  (4.22e-20, 4.62e-50j)
| (0.026005678400867750431 + 1.7798851796998986169e-140j)  +/-  (9.7e-21, 1.06e-50j)
| (0.11463522019827456925 - 1.0549642541089065145e-140j)  +/-  (3.12e-20, 3.6e-50j)
| (0.23036016700500592493 - 1.1414709624410397843e-140j)  +/-  (6.71e-20, 8.1e-50j)
| (0.22366680318204946821 + 3.9091296938162569478e-140j)  +/-  (9.01e-20, 1.12e-49j)
| (0.11463522019827456925 + 6.7206549521494151391e-140j)  +/-  (2.1e-20, 2.77e-50j)
| (0.015614589894054148587 - 1.1447631149645586456e-140j)  +/-  (1.55e-21, 1.6e-51j)
