Starting with polynomial:
P : 4096*t^12 - 135168*t^10 + 1520640*t^8 - 7096320*t^6 + 13305600*t^4 - 7983360*t^2 + 665280
Extension levels are: 12 21
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Trying to find an order 21 Kronrod extension for:
P1 : 4096*t^12 - 135168*t^10 + 1520640*t^8 - 7096320*t^6 + 13305600*t^4 - 7983360*t^2 + 665280
Solvable: 1
-------------------------------------------------
Ending with final polynomial:
P : 4096*t^33 - 169531266432/193249*t^31 + 205391409315840/2512237*t^29 - 11005875364276320/2512237*t^27 + 377600440796805600/2512237*t^25 - 8744563582324768440/2512237*t^23 + 20065862603796237360/358891*t^21 - 226288979819213567850/358891*t^19 + 94433917626447651450/18889*t^17 - 1044815980504160192625/37778*t^15 + 1982227677164601713550/18889*t^13 - 3086482588843958417025/11624*t^11 + 4986513451688993222625/11624*t^9 - 19245077839616143717125/46496*t^7 + 4975584239837721943125/23248*t^5 - 9059923977142930439625/185984*t^3 + 573488939085422196375/185984*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
-------------------------------------------------
The nodes are:
| (3.8897248978697819193 + 9.7325837686576147061e-430j)  +/-  (3.2e-120, 3.2e-120j)
| (-6.8710234528999108769 - 2.5780386988075612658e-432j)  +/-  (5.22e-122, 5.22e-122j)
| (6.8710234528999108769 - 5.6440148731019059517e-437j)  +/-  (5.73e-122, 5.73e-122j)
| (-3.8897248978697819193 + 3.3369049539234834828e-434j)  +/-  (3.18e-120, 3.18e-120j)
| (6.075759406572362672 + 2.7273702075534040163e-442j)  +/-  (4.02e-121, 4.02e-121j)
| (-6.075759406572362672 + 2.845868658284411417e-442j)  +/-  (4.29e-121, 4.29e-121j)
| (4.3682757906545641047 - 1.2526225444928830215e-448j)  +/-  (3.57e-120, 3.57e-120j)
| (-4.8813357634869789591 - 3.1454392033669696512e-455j)  +/-  (2.73e-120, 2.73e-120j)
| (5.4412465799975483203 - 1.3559095293524696729e-463j)  +/-  (1.47e-120, 1.47e-120j)
| (1.5976826351526047967 - 2.2592270748621536252e-467j)  +/-  (1.64e-122, 1.64e-122j)
| (-5.4412465799975483203 - 2.6564368290879606932e-468j)  +/-  (1.45e-120, 1.45e-120j)
| (4.8813357634869789591 - 7.5784270335732002214e-471j)  +/-  (2.57e-120, 2.57e-120j)
| (-3.4404981661410129918 + 5.7865246107922603473e-473j)  +/-  (2.56e-120, 2.56e-120j)
| (-1.2657288367899360722 - 3.5185995690027752929e-478j)  +/-  (2.68e-123, 2.68e-123j)
| (3.4404981661410129918 - 6.6257559382038821457e-475j)  +/-  (2.42e-120, 2.42e-120j)
| (3.0206370251208897717 - 1.9384489604698391819e-478j)  +/-  (1.58e-120, 1.58e-120j)
| (1.2657288367899360722 - 1.0469170504496339115e-482j)  +/-  (2.48e-123, 2.48e-123j)
| (2.2795070805010599002 - 6.1550403786754838275e-480j)  +/-  (2.98e-121, 2.98e-121j)
| (-0.9477883912401637437 - 1.2543374481719700867e-482j)  +/-  (3.5e-124, 3.5e-124j)
| (-3.0206370251208897717 + 8.0237710468074118638e-479j)  +/-  (1.54e-120, 1.54e-120j)
| (-1.9384540920224533815 - 3.7458531454985098484e-483j)  +/-  (7.66e-122, 7.66e-122j)
| (0.63213226703101579637 - 1.7652274633696316964e-486j)  +/-  (3.5e-125, 3.5e-125j)
| (-2.6340734136644987064 - 2.300540675942480141e-481j)  +/-  (8.59e-121, 8.59e-121j)
| (-0.31424037625435911128 + 2.6195644428322794536e-491j)  +/-  (2.99e-126, 2.99e-126j)
| (-1.5976826351526047967 + 2.893268849945659242e-486j)  +/-  (1.76e-122, 1.76e-122j)
| (1.9384540920224533815 - 3.8638569906552330598e-487j)  +/-  (7.83e-122, 7.83e-122j)
| (0.31424037625435911128 + 1.591452518168120112e-490j)  +/-  (2.99e-126, 2.99e-126j)
| (-1.7683698015932126848e-494 - 1.3494681652760969787e-495j)  +/-  (5.85e-493, 5.85e-493j)
| (-2.2795070805010599002 - 6.8583173572672270043e-485j)  +/-  (2.82e-121, 2.82e-121j)
| (-0.63213226703101579637 + 2.9588357527476606932e-493j)  +/-  (3.91e-125, 3.91e-125j)
| (-4.3682757906545641047 - 3.9432499162327047046e-492j)  +/-  (3.2e-120, 3.2e-120j)
| (2.6340734136644987064 + 4.1960391534380038703e-495j)  +/-  (7.63e-121, 7.63e-121j)
| (0.9477883912401637437 - 4.9810012482243760805e-500j)  +/-  (3.43e-124, 3.43e-124j)
-------------------------------------------------
The weights are:
| (7.0241986351229608354e-08 - 3.5865371649434292917e-436j)  +/-  (6.75e-36, 1.27e-94j)
| (1.7031980757140935515e-21 + 8.8157261597877337522e-446j)  +/-  (2.04e-44, 3.85e-103j)
| (1.7031980757140935515e-21 - 3.1816004101162635154e-445j)  +/-  (2.76e-44, 5.19e-103j)
| (7.0241986351229608354e-08 - 8.7754199090783938231e-438j)  +/-  (1.23e-37, 2.32e-96j)
| (3.6163947593646578788e-17 + 8.8568697141469678942e-443j)  +/-  (1.08e-42, 2.03e-101j)
| (3.6163947593646578788e-17 - 1.943137096308561705e-443j)  +/-  (1.91e-43, 3.59e-102j)
| (1.4402041153833014942e-09 - 1.1238843180461680624e-437j)  +/-  (5.25e-39, 9.88e-98j)
| (1.3505848071778103229e-11 - 3.4483505643112325466e-440j)  +/-  (2.4e-41, 4.53e-100j)
| (4.6169328763194783924e-14 - 6.9480265573373694342e-441j)  +/-  (6.71e-42, 1.26e-100j)
| (0.014876927885944634827 - 4.6392673718123531864e-433j)  +/-  (2.89e-31, 5.43e-90j)
| (4.6169328763194783924e-14 + 1.1555254343384756651e-441j)  +/-  (7.67e-43, 1.44e-101j)
| (1.3505848071778103229e-11 + 3.0492445265002325858e-439j)  +/-  (1.02e-40, 1.91e-99j)
| (1.7746949078648174161e-06 + 9.0606954761464809067e-437j)  +/-  (3.99e-39, 7.52e-98j)
| (0.036840944498752074726 + 4.6835186371926093924e-433j)  +/-  (1.16e-31, 2.18e-90j)
| (1.7746949078648174161e-06 + 1.4792966119902399015e-435j)  +/-  (2.16e-38, 4.07e-97j)
| (2.4841170013685313486e-05 - 5.8331411795149003102e-435j)  +/-  (6.21e-38, 1.17e-96j)
| (0.036840944498752074726 + 9.202326678182733478e-433j)  +/-  (2.53e-33, 4.76e-92j)
| (0.0010740729027396747919 - 7.7299748246116552522e-434j)  +/-  (1.22e-36, 2.31e-95j)
| (0.072244625679194799292 - 9.2185665860531274075e-433j)  +/-  (7.51e-34, 1.41e-92j)
| (2.4841170013685313486e-05 - 7.3341340072630153953e-436j)  +/-  (4.3e-40, 8.11e-99j)
| (0.0044894929212943745126 + 6.8332362037434754138e-434j)  +/-  (3.89e-38, 7.33e-97j)
| (0.12018767238488778267 + 2.0634656355497082139e-432j)  +/-  (1.06e-35, 2e-94j)
| (0.00020190394859705160263 + 4.5202086564341642881e-435j)  +/-  (8.21e-40, 1.55e-98j)
| (0.16182409309081578436 - 2.0458348237262197017e-432j)  +/-  (3.16e-36, 5.93e-95j)
| (0.014876927885944634827 - 1.9376501958011191797e-433j)  +/-  (9.49e-38, 1.79e-96j)
| (0.0044894929212943745126 + 2.0411797971890632063e-433j)  +/-  (1.12e-38, 2.12e-97j)
| (0.16182409309081578436 - 2.4054682461584031857e-432j)  +/-  (1.68e-36, 3.15e-95j)
| (0.17646715825421950581 + 2.4105714120729869513e-432j)  +/-  (1.2e-36, 2.26e-95j)
| (0.0010740729027396747919 - 2.0173369250319145673e-434j)  +/-  (2.07e-39, 3.89e-98j)
| (0.12018767238488778267 + 1.4865079347091232658e-432j)  +/-  (4.59e-37, 8.64e-96j)
| (1.4402041153833014942e-09 + 6.5167465509581714416e-439j)  +/-  (2.6e-44, 4.89e-103j)
| (0.00020190394859705160263 + 2.3488993123676281423e-434j)  +/-  (6.51e-41, 1.29e-99j)
| (0.072244625679194799292 - 1.5158900520570205985e-432j)  +/-  (2.41e-38, 4.1e-97j)
