Starting with polynomial:
P : 1048576*t^21 - 5505024*t^19 + 12386304*t^17 - 15597568*t^15 + 12042240*t^13 - 5870592*t^11 + 1793792*t^9 - 329472*t^7 + 33264*t^5 - 1540*t^3 + 21*t
Extension levels are: 21 42
-------------------------------------------------
Trying to find an order 42 Kronrod extension for:
P1 : 1048576*t^21 - 5505024*t^19 + 12386304*t^17 - 15597568*t^15 + 12042240*t^13 - 5870592*t^11 + 1793792*t^9 - 329472*t^7 + 33264*t^5 - 1540*t^3 + 21*t
Solvable: 1
-------------------------------------------------
Ending with final polynomial:
P : 1048576*t^63 - 16515072*t^61 + 123863040*t^59 - 588693504*t^57 + 1990582272*t^55 - 5096577024*t^53 + 10267665408*t^51 - 16698052800*t^49 + 22314670560*t^47 - 24817035880*t^45 + 23178175020*t^43 - 36590720355/2*t^41 + 49026782175/4*t^39 - 111781063359/16*t^37 + 108522140229/32*t^35 - 1434903854139/1024*t^33 + 1007485684821/2048*t^31 - 1198160724915/8192*t^29 + 600559573229/16384*t^27 - 1008595264131/131072*t^25 + 351835557255/262144*t^23 - 201846702915/1048576*t^21 + 46993134825/2097152*t^19 - 69876748305/33554432*t^17 + 10153031805/67108864*t^15 - 2244354399/268435456*t^13 + 181974681/536870912*t^11 - 41187685/4294967296*t^9 + 1513017/8589934592*t^7 - 64449/34359738368*t^5 + 651/68719476736*t^3 - 63/4398046511104*t
-------------------------------------------------
Computing nodes and weights
  current precision for roots: 53
  current precision for roots: 106
  current precision for roots: 212
 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: 0
  current precision for roots: 212
  current precision for roots: 424
 current precision for weights: 212
Linear system for weights solvable: 1
  current precision for roots: 424
  current precision for roots: 848
 current precision for weights: 424
Linear system for weights solvable: 1
Sufficient bits for target precision reached
Positive weights:   63 out of 63
Indefinite weights: 0 out of 63
Negative weights:   0 out of 63
Extension rule has valid weights: 1
-------------------------------------------------
The nodes are:
| (0.99223920660017208063 - 1.1883399843046819555e-885j)  +/-  (4.86e-233, 4.86e-233j)
| (-0.97492791218182360702 - 7.3772995983038196753e-894j)  +/-  (4.25e-233, 4.25e-233j)
| (-0.91150585231167315178 + 2.5043486796875782255e-896j)  +/-  (4.42e-234, 4.42e-234j)
| (-0.99223920660017208063 + 6.497199340322218201e-894j)  +/-  (5.13e-233, 5.13e-233j)
| (0.94792734616713175592 + 1.9359611528689836459e-895j)  +/-  (2.11e-233, 2.11e-233j)
| (0.93087374864420425564 - 4.626524171349843939e-903j)  +/-  (1e-233, 1e-233j)
| (-0.99720379718118014823 - 5.8085669088140328664e-902j)  +/-  (3.92e-233, 3.92e-233j)
| (-0.88987180881146860569 + 2.6362159996683349409e-907j)  +/-  (1.81e-234, 1.81e-234j)
| (0.99968918200081628415 + 1.4505615566199042792e-903j)  +/-  (1.38e-233, 1.38e-233j)
| (-0.99968918200081628415 - 1.7516674812459800729e-919j)  +/-  (1.35e-233, 1.35e-233j)
| (0.84002592315077144274 + 2.817454964651048487e-927j)  +/-  (2.16e-235, 2.16e-235j)
| (0.9626242469500120742 - 1.0711897014936790728e-923j)  +/-  (2.91e-233, 2.91e-233j)
| (-0.93087374864420425564 - 2.2112330822189558868e-936j)  +/-  (8.64e-234, 8.64e-234j)
| (-0.86602540378443864676 - 6.0995376895838417606e-938j)  +/-  (6.22e-235, 6.22e-235j)
| (-0.9626242469500120742 - 9.4878089491921212185e-936j)  +/-  (2.95e-233, 2.95e-233j)
| (0.86602540378443864676 - 1.092494557479004418e-935j)  +/-  (5.68e-235, 5.68e-235j)
| (0.88987180881146860569 + 1.6502139775641687829e-934j)  +/-  (1.77e-234, 1.77e-234j)
| (0.98480775301220805937 + 1.9355391866446840976e-945j)  +/-  (5.89e-233, 5.89e-233j)
| (-0.78183148246802980871 - 6.7068790192513148613e-971j)  +/-  (1.27e-236, 1.27e-236j)
| (-0.94792734616713175592 - 5.017676051989434021e-966j)  +/-  (1.72e-233, 1.72e-233j)
| (0.8119380057158564946 - 1.0525431148095141396e-967j)  +/-  (4.79e-236, 4.79e-236j)
| (0.74978120296773417255 - 1.4595850628408355893e-970j)  +/-  (2.73e-237, 2.73e-237j)
| (0.99720379718118014823 + 6.6546452484967857615e-970j)  +/-  (3.79e-233, 3.79e-233j)
| (-0.84002592315077144274 - 3.2013690503947285278e-986j)  +/-  (1.82e-235, 1.82e-235j)
| (-0.8119380057158564946 + 1.6352849594985436701e-987j)  +/-  (5.64e-236, 5.64e-236j)
| (0.91150585231167315178 + 4.4934392048409261268e-983j)  +/-  (4.19e-234, 4.19e-234j)
| (0.71586684925971843583 - 1.5016984299646105652e-989j)  +/-  (5.94e-238, 5.94e-238j)
| (0.78183148246802980871 - 1.5671847574050512993e-987j)  +/-  (1.25e-236, 1.25e-236j)
| (-0.47825397862131821173 - 1.4882490309387712088e-996j)  +/-  (1.75e-243, 1.75e-243j)
| (-0.64278760968653932632 + 2.2489123967678089368e-993j)  +/-  (1.2e-239, 1.2e-239j)
| (0.14904226617617444693 - 2.6993936623820445229e-1006j)  +/-  (4.99e-252, 4.99e-252j)
| (0.97492791218182360702 + 2.3830838809010145585e-989j)  +/-  (4.14e-233, 4.14e-233j)
| (0.68017273777091939019 - 7.0477840409704411623e-1002j)  +/-  (8.41e-239, 8.41e-239j)
| (-0.98480775301220805937 - 1.9448066925075160997e-1001j)  +/-  (5.19e-233, 5.19e-233j)
| (-0.68017273777091939019 + 1.7055351794973886957e-1010j)  +/-  (8.84e-239, 8.84e-239j)
| (-0.74978120296773417255 + 5.1130657891488055884e-1010j)  +/-  (2.81e-237, 2.81e-237j)
| (0.04984588566069716295 + 2.5433546945227717915e-1031j)  +/-  (1.04e-254, 1.04e-254j)
| (0.56332005806362202775 + 3.4550515546016859465e-1019j)  +/-  (2.07e-241, 2.07e-241j)
| (0.52143520337949807243 - 5.5097662007991248589e-1020j)  +/-  (1.94e-242, 1.94e-242j)
| (-0.71586684925971843583 + 1.4558264793314758773e-1016j)  +/-  (4.99e-238, 4.99e-238j)
| (-0.52143520337949807243 - 5.2898333980209695737e-1021j)  +/-  (1.9e-242, 1.9e-242j)
| (-0.24675739769029363837 + 4.1262214720479863797e-1029j)  +/-  (2.33e-249, 2.33e-249j)
| (0.43388373911755812048 - 3.5155229762058984438e-1024j)  +/-  (1.35e-244, 1.35e-244j)
| (0.60380441032547736874 - 1.4157201321912299097e-1022j)  +/-  (1.57e-240, 1.57e-240j)
| (-2.9296023897961329012e-1054 + 1.4810439329568540772e-1053j)  +/-  (9.51e-1052, 9.51e-1052j)
| (-0.56332005806362202775 - 2.5410537174599931706e-1019j)  +/-  (2.28e-241, 2.28e-241j)
| (-0.60380441032547736874 + 1.0757447581007104397e-1022j)  +/-  (1.76e-240, 1.76e-240j)
| (0.64278760968653932632 + 2.1710038478609992916e-1027j)  +/-  (1.32e-239, 1.32e-239j)
| (0.47825397862131821173 - 7.4195407398292036317e-1030j)  +/-  (1.99e-243, 1.99e-243j)
| (0.19814614319939758337 - 1.6650340822758281763e-1036j)  +/-  (1.26e-250, 1.26e-250j)
| (-0.19814614319939758337 - 4.0931370525359950643e-1036j)  +/-  (1.1e-250, 1.1e-250j)
| (-0.43388373911755812048 - 2.5358531646809945995e-1029j)  +/-  (1.28e-244, 1.28e-244j)
| (-0.04984588566069716295 + 2.1463534921162653062e-1040j)  +/-  (1.04e-254, 1.04e-254j)
| (0.34202014332566873304 - 4.5338168742079601194e-1032j)  +/-  (6.76e-247, 6.76e-247j)
| (0.29475517441090421683 + 2.0869381934661315496e-1034j)  +/-  (4.23e-248, 4.23e-248j)
| (-0.099567846595816657186 + 2.2166630383119527161e-1038j)  +/-  (2.37e-253, 2.37e-253j)
| (-0.38843479627469471189 + 8.7981564760774240359e-1031j)  +/-  (1.13e-245, 1.13e-245j)
| (-0.14904226617617444693 + 1.7651081949489140246e-1037j)  +/-  (4.65e-252, 4.65e-252j)
| (0.24675739769029363837 + 9.142528565764771567e-1035j)  +/-  (2.15e-249, 2.15e-249j)
| (0.38843479627469471189 + 6.1753213828514129479e-1031j)  +/-  (9.7e-246, 9.7e-246j)
| (0.099567846595816657186 - 3.6726534211315699935e-1038j)  +/-  (2.73e-253, 2.73e-253j)
| (-0.29475517441090421683 - 2.3615988985168084648e-1033j)  +/-  (4.16e-248, 4.16e-248j)
| (-0.34202014332566873304 - 1.5608454215014282388e-1033j)  +/-  (6.87e-247, 6.87e-247j)
-------------------------------------------------
The weights are:
| (0.015873015873015873016 + 6.052557774177650304e-886j)  +/-  (1.99e-40, 1.12e-150j)
| (0.015873015873015873016 + 1.7159562715383039841e-887j)  +/-  (9.76e-41, 5.5e-151j)
| (0.015873015873015873016 + 3.2772733867337873053e-887j)  +/-  (4.05e-41, 2.28e-151j)
| (0.015873015873015873016 + 9.505043426999999436e-888j)  +/-  (3.85e-41, 2.17e-151j)
| (0.015873015873015873016 + 1.0903040043369399139e-885j)  +/-  (1.38e-42, 7.8e-153j)
| (0.015873015873015873016 - 9.0313114773805637117e-886j)  +/-  (1.16e-42, 6.55e-153j)
| (0.015873015873015873016 - 5.6982246346954872199e-888j)  +/-  (1.22e-41, 6.89e-152j)
| (0.015873015873015873016 - 3.6770247977981071137e-887j)  +/-  (6.68e-43, 3.76e-153j)
| (0.015873015873015873016 - 5.0764001507765696848e-886j)  +/-  (3.14e-44, 1.77e-154j)
| (0.015873015873015873016 + 1.8986130085985233777e-888j)  +/-  (5.77e-42, 3.25e-152j)
| (0.015873015873015873016 - 5.4070524337544700354e-886j)  +/-  (4.37e-45, 2.46e-155j)
| (0.015873015873015873016 - 1.3873267774763749135e-885j)  +/-  (7.76e-44, 4.37e-154j)
| (0.015873015873015873016 - 2.8818409962832555471e-887j)  +/-  (3.35e-43, 1.89e-153j)
| (0.015873015873015873016 + 4.0816787073040938242e-887j)  +/-  (2.06e-44, 1.16e-154j)
| (0.015873015873015873016 - 2.1017129674818941757e-887j)  +/-  (2.27e-43, 1.28e-153j)
| (0.015873015873015873016 + 6.0095162024570672599e-886j)  +/-  (2.1e-45, 1.18e-155j)
| (0.015873015873015873016 - 6.7605202999317299048e-886j)  +/-  (2.22e-45, 1.25e-155j)
| (0.015873015873015873016 - 3.5446455864173072496e-885j)  +/-  (4.63e-45, 2.61e-155j)
| (0.015873015873015873016 - 5.3313205814417942231e-887j)  +/-  (1.42e-47, 8e-158j)
| (0.015873015873015873016 + 2.4901675736154078742e-887j)  +/-  (1e-43, 5.64e-154j)
| (0.015873015873015873016 + 4.9113391468293631233e-886j)  +/-  (1.77e-47, 9.96e-158j)
| (0.015873015873015873016 + 4.139917367969430626e-886j)  +/-  (4.29e-49, 2.42e-159j)
| (0.015873015873015873016 + 2.2834339057668068556e-885j)  +/-  (1.38e-45, 7.77e-156j)
| (0.015873015873015873016 - 4.4918456765304274172e-887j)  +/-  (1.68e-47, 9.44e-158j)
| (0.015873015873015873016 + 4.9081673045545652105e-887j)  +/-  (3.2e-48, 1.8e-158j)
| (0.015873015873015873016 + 7.7280238345413701949e-886j)  +/-  (6.99e-47, 3.94e-157j)
| (0.015873015873015873016 - 3.8325206270285129653e-886j)  +/-  (7.47e-51, 4.21e-161j)
| (0.015873015873015873016 - 4.4951483997312858769e-886j)  +/-  (3.95e-49, 2.22e-159j)
| (0.015873015873015873016 - 9.0597757011216509359e-887j)  +/-  (2.3e-55, 1.3e-165j)
| (0.015873015873015873016 - 7.1073131099887732576e-887j)  +/-  (4.15e-54, 2.34e-164j)
| (0.015873015873015873016 + 1.778972905702604091e-886j)  +/-  (2.5e-57, 1.41e-167j)
| (0.015873015873015873016 + 1.949924022837904137e-885j)  +/-  (2.71e-48, 1.53e-158j)
| (0.015873015873015873016 + 3.5633949378902428234e-886j)  +/-  (6.68e-53, 3.76e-163j)
| (0.015873015873015873016 - 1.332387459395198726e-887j)  +/-  (4.7e-49, 2.65e-159j)
| (0.015873015873015873016 + 6.6491756974229789098e-887j)  +/-  (6.12e-54, 3.45e-164j)
| (0.015873015873015873016 + 5.7620226894180800634e-887j)  +/-  (1.01e-52, 5.66e-163j)
| (0.015873015873015873016 + 1.6076961119850671269e-886j)  +/-  (9.6e-59, 5.4e-169j)
| (0.015873015873015873016 - 2.9221768461375144236e-886j)  +/-  (9.01e-57, 5.07e-167j)
| (0.015873015873015873016 + 2.7493708025285364843e-886j)  +/-  (2.08e-57, 1.17e-167j)
| (0.015873015873015873016 - 6.2010363344318959178e-887j)  +/-  (1.72e-54, 9.69e-165j)
| (0.015873015873015873016 + 8.5514743371952098082e-887j)  +/-  (6.83e-58, 3.84e-168j)
| (0.015873015873015873016 + 1.1864915729405832314e-886j)  +/-  (1.01e-60, 5.66e-171j)
| (0.015873015873015873016 + 2.4477968414212424237e-886j)  +/-  (1.11e-59, 6.23e-170j)
| (0.015873015873015873016 + 3.113069031580464934e-886j)  +/-  (2.4e-57, 1.35e-167j)
| (0.015873015873015873016 - 1.528832743850736315e-886j)  +/-  (3.05e-61, 1.71e-171j)
| (0.015873015873015873016 - 8.0574082966443334231e-887j)  +/-  (1.91e-58, 1.08e-168j)
| (0.015873015873015873016 + 7.5763865776698219276e-887j)  +/-  (6.2e-58, 3.49e-168j)
| (0.015873015873015873016 - 3.3253954295063787656e-886j)  +/-  (5.11e-58, 2.88e-168j)
| (0.015873015873015873016 - 2.5919691150978412682e-886j)  +/-  (4.91e-60, 2.77e-170j)
| (0.015873015873015873016 - 1.8724380794821583497e-886j)  +/-  (8.93e-63, 5.03e-173j)
| (0.015873015873015873016 - 1.2490829907946479572e-886j)  +/-  (1.1e-63, 6.2e-174j)
| (0.015873015873015873016 + 9.5836110018946160226e-887j)  +/-  (1.83e-62, 1.03e-172j)
| (0.015873015873015873016 + 1.453894782557718911e-886j)  +/-  (9.75e-64, 5.49e-174j)
| (0.015873015873015873016 + 2.1923125853900658658e-886j)  +/-  (1.08e-63, 6.07e-174j)
| (0.015873015873015873016 - 2.0782886747715680532e-886j)  +/-  (5.46e-64, 3.08e-174j)
| (0.015873015873015873016 - 1.3825058478057598974e-886j)  +/-  (8.98e-65, 5.06e-175j)
| (0.015873015873015873016 - 1.0124401067843628686e-886j)  +/-  (3.5e-65, 1.97e-175j)
| (0.015873015873015873016 + 1.3143335353538843722e-886j)  +/-  (4.66e-65, 2.62e-175j)
| (0.015873015873015873016 + 1.9719582816802014684e-886j)  +/-  (3.72e-65, 2.1e-175j)
| (0.015873015873015873016 - 2.3150704203409666091e-886j)  +/-  (5.62e-65, 3.16e-175j)
| (0.015873015873015873016 - 1.6909130304582231321e-886j)  +/-  (1.63e-65, 9.19e-176j)
| (0.015873015873015873016 - 1.126324395750177461e-886j)  +/-  (8.05e-67, 4.54e-177j)
| (0.015873015873015873016 + 1.06837058326630283e-886j)  +/-  (7.64e-67, 4.29e-177j)
