Starting with polynomial:
P : 16384*t^14 - 745472*t^12 + 12300288*t^10 - 92252160*t^8 + 322882560*t^6 - 484323840*t^4 + 242161920*t^2 - 17297280
Extension levels are: 14 21
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Trying to find an order 21 Kronrod extension for:
P1 : 16384*t^14 - 745472*t^12 + 12300288*t^10 - 92252160*t^8 + 322882560*t^6 - 484323840*t^4 + 242161920*t^2 - 17297280
Solvable: 1
-------------------------------------------------
Ending with final polynomial:
P : 16384*t^35 - 19511224928418664448/5631204568669*t^33 + 1811432805868971005952/5631204568669*t^31 - 97688719703614733675520/5631204568669*t^29 + 3413190472125801059320320/5631204568669*t^27 - 81610243428647844349528320/5631204568669*t^25 + 1375401496517791922597362560/5631204568669*t^23 - 16585770274687365016570683840/5631204568669*t^21 + 143828251810737506803258221600/5631204568669*t^19 - 894168390672092388946795455600/5631204568669*t^17 + 3942595463164206290936269360200/5631204568669*t^15 - 12094144305738121539194898716100/5631204568669*t^13 + 25052733061575490801325147502150/5631204568669*t^11 - 33523359691647467115337968979875/5631204568669*t^9 + 54218777654213764582818516814125/11262409137338*t^7 - 47677020587632395731353659202125/22524818274676*t^5 + 18784825074919843024745829794625/45049636549352*t^3 - 514294395565125885913297969875/22524818274676*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: 0
  current precision for roots: 106
  current precision for roots: 212
 current precision for weights: 106
Linear system for weights solvable: 1
  current precision for roots: 212
  current precision for roots: 424
 current precision for weights: 212
Linear system for weights solvable: 1
Sufficient bits for target precision reached
Positive weights:   35 out of 35
Indefinite weights: 0 out of 35
Negative weights:   0 out of 35
Extension rule has valid weights: 1
-------------------------------------------------
The nodes are:
| (4.7924932754391695579 - 5.6023395711830138504e-416j)  +/-  (6.03e-120, 6.03e-120j)
| (-4.7924932754391695579 - 1.7641836567595346328e-417j)  +/-  (5.79e-120, 5.79e-120j)
| (3.1042184728306519392 + 4.9227196061169628901e-417j)  +/-  (6.98e-120, 6.98e-120j)
| (3.8595520344178473401 + 3.7014236169543389861e-416j)  +/-  (9.49e-120, 9.49e-120j)
| (5.928183371975010356 + 7.2121701463245734352e-418j)  +/-  (8.48e-121, 8.48e-121j)
| (6.6520434397831051819 - 4.0358610538434822786e-419j)  +/-  (1.05e-121, 1.05e-121j)
| (-5.928183371975010356 - 2.9279238690442561558e-418j)  +/-  (7.9e-121, 7.9e-121j)
| (-6.6520434397831051819 - 2.0742357234893932208e-420j)  +/-  (1.03e-121, 1.03e-121j)
| (5.3274657934400337894 - 1.0369671545489692398e-418j)  +/-  (3.07e-120, 3.07e-120j)
| (4.3044485704736318126 - 5.2699376908567516079e-419j)  +/-  (9.19e-120, 9.19e-120j)
| (0.60646643196812249066 - 2.1326329006042939155e-423j)  +/-  (4.6e-125, 4.6e-125j)
| (-5.3274657934400337894 - 5.2354451549690596213e-418j)  +/-  (2.8e-120, 2.8e-120j)
| (-2.0951832585077168157 + 3.9784779655293398225e-418j)  +/-  (5.36e-121, 5.36e-121j)
| (-1.1438025769590317961 + 6.2300763943538967479e-429j)  +/-  (2.87e-123, 2.87e-123j)
| (-3.4626569336022705502 - 1.8741041709011905127e-426j)  +/-  (9.59e-120, 9.59e-120j)
| (1.1438025769590317961 + 1.0429324958373868961e-438j)  +/-  (3.07e-123, 3.07e-123j)
| (1.4766827311411408706 - 3.0794263169160265834e-437j)  +/-  (1.92e-122, 1.92e-122j)
| (-2.3965135920720816869 + 1.8558441848149992546e-441j)  +/-  (1.47e-120, 1.47e-120j)
| (-1.811759462900802804 - 2.0742756230264418649e-451j)  +/-  (1.5e-121, 1.5e-121j)
| (2.7484707249854025686 - 1.1143346505627073725e-452j)  +/-  (3.4e-120, 3.4e-120j)
| (2.0951832585077168157 - 1.8127123899789548756e-454j)  +/-  (5.57e-121, 5.57e-121j)
| (3.4626569336022705502 + 3.7919665093688046522e-456j)  +/-  (9.54e-120, 9.54e-120j)
| (-2.7484707249854025686 + 4.1917218322266563153e-463j)  +/-  (3.49e-120, 3.49e-120j)
| (-0.29174551067256207845 + 2.1599815666671297856e-477j)  +/-  (2.7e-126, 2.7e-126j)
| (-0.87871378732939941611 + 3.0564024802837654772e-475j)  +/-  (4.71e-124, 4.71e-124j)
| (-3.1042184728306519392 + 3.9509887273378668363e-470j)  +/-  (7.18e-120, 7.18e-120j)
| (0.87871378732939941611 + 2.3546220784903777838e-479j)  +/-  (4.75e-124, 4.75e-124j)
| (0.29174551067256207845 - 2.0063221859105257239e-481j)  +/-  (2.7e-126, 2.7e-126j)
| (3.3505943894313251797e-487 + 3.9867907541234008034e-486j)  +/-  (1.4e-484, 1.4e-484j)
| (-0.60646643196812249066 + 1.385351913603994266e-479j)  +/-  (4.37e-125, 4.37e-125j)
| (-4.3044485704736318126 - 1.8767769863113348755e-475j)  +/-  (8.91e-120, 8.91e-120j)
| (1.811759462900802804 - 5.287611844514069562e-478j)  +/-  (1.41e-121, 1.41e-121j)
| (2.3965135920720816869 + 4.6861909790112663235e-480j)  +/-  (1.51e-120, 1.51e-120j)
| (-3.8595520344178473401 + 9.0156147557323502495e-482j)  +/-  (1.04e-119, 1.04e-119j)
| (-1.4766827311411408706 - 7.581466999450737514e-486j)  +/-  (1.82e-122, 1.82e-122j)
-------------------------------------------------
The weights are:
| (3.0479420438537346475e-11 + 2.1321601167592414773e-425j)  +/-  (1.46e-33, 1.15e-92j)
| (3.0479420438537346475e-11 - 1.3099110676729077614e-426j)  +/-  (1.97e-34, 1.55e-93j)
| (1.2968659737396588975e-05 - 5.9429067851092882454e-421j)  +/-  (8.42e-28, 6.63e-87j)
| (8.0770507530746917578e-08 - 1.7000820003989858044e-422j)  +/-  (9.37e-31, 7.38e-90j)
| (1.9924472618629307349e-16 + 1.3997767700925586098e-429j)  +/-  (1.51e-37, 1.19e-96j)
| (2.8539195415094885164e-20 - 5.5004402243810338025e-432j)  +/-  (1.46e-39, 1.15e-98j)
| (1.9924472618629307349e-16 - 3.5732811480820243305e-430j)  +/-  (2.29e-40, 1.8e-99j)
| (2.8539195415094885164e-20 + 1.6384397941524859129e-432j)  +/-  (2.88e-42, 2.26e-101j)
| (1.4990312213590645719e-13 - 9.561557824319198964e-428j)  +/-  (6.67e-37, 5.25e-96j)
| (2.3650649053314876008e-09 - 5.4049753180755853856e-424j)  +/-  (2.64e-34, 2.08e-93j)
| (0.1196390004364415525 - 2.9721232514235283422e-418j)  +/-  (3.15e-25, 2.48e-84j)
| (1.4990312213590645719e-13 + 2.2648636041884866456e-428j)  +/-  (3.33e-39, 2.62e-98j)
| (0.0019032802140294997022 + 7.5657971780732585267e-420j)  +/-  (9.84e-31, 7.74e-90j)
| (0.046538082822621732956 - 8.7348004461179460723e-419j)  +/-  (2.92e-25, 2.3e-84j)
| (1.3053583686557017499e-06 + 4.3704463684548194595e-423j)  +/-  (5.85e-36, 4.6e-95j)
| (0.046538082822621732956 - 1.5302904430430346036e-418j)  +/-  (2.3e-26, 1.81e-85j)
| (0.022083558460254768964 + 6.8533568536512543994e-419j)  +/-  (1.94e-28, 1.53e-87j)
| (0.0006054279997814289807 - 5.3319613186226254289e-421j)  +/-  (1.54e-32, 1.21e-91j)
| (0.0066018912293446444828 - 1.7734046435257052445e-419j)  +/-  (2.78e-30, 2.19e-89j)
| (0.00010623115468476130207 + 2.0269033066496264775e-420j)  +/-  (8.31e-34, 6.54e-93j)
| (0.0019032802140294997022 + 1.8716939309879551596e-419j)  +/-  (1.84e-32, 1.44e-91j)
| (1.3053583686557017499e-06 + 5.0368585064425902236e-422j)  +/-  (2.85e-35, 2.24e-94j)
| (0.00010623115468476130207 + 1.6026318167039986868e-421j)  +/-  (4.63e-35, 3.64e-94j)
| (0.16014430462212895798 + 2.7169483018356097924e-418j)  +/-  (5.6e-30, 4.39e-89j)
| (0.063302869860882087344 + 1.6627884190863189203e-418j)  +/-  (2.4e-30, 1.88e-89j)
| (1.2968659737396588975e-05 - 3.0301646010981676901e-422j)  +/-  (2.49e-36, 1.96e-95j)
| (0.063302869860882087344 + 2.5667359780572814732e-418j)  +/-  (1.51e-30, 1.18e-89j)
| (0.16014430462212895798 + 3.1393362323292686693e-418j)  +/-  (1.41e-30, 1.1e-89j)
| (0.15812199203104510916 - 3.2007266274609298709e-418j)  +/-  (9.95e-31, 7.77e-90j)
| (0.1196390004364415525 - 2.2011366574074315299e-418j)  +/-  (1.56e-31, 1.22e-90j)
| (2.3650649053314876008e-09 + 2.5470778464744505221e-425j)  +/-  (2.84e-40, 2.22e-99j)
| (0.0066018912293446444828 - 3.6340752142808507489e-419j)  +/-  (6.71e-34, 5.12e-93j)
| (0.0006054279997814289807 - 6.6760032772182608901e-420j)  +/-  (4.28e-35, 3.26e-94j)
| (8.0770507530746917578e-08 - 4.0458382253761501908e-424j)  +/-  (2.65e-39, 2.13e-98j)
| (0.022083558460254768964 + 3.4063089522091868451e-419j)  +/-  (4.02e-34, 2.87e-93j)
