Starting with polynomial:
P : t
Extension levels are: 1 18 20
-------------------------------------------------
Trying to find an order 18 Kronrod extension for:
P1 : t
Solvable: 1
-------------------------------------------------
Trying to find an order 20 Kronrod extension for:
P2 : t^19 - 171/37*t^17 + 11628/1295*t^15 - 3876/407*t^13 + 75582/12617*t^11 - 75582/33263*t^9 + 16796/33263*t^7 - 50388/831575*t^5 + 12597/3825245*t^3 - 4199/80330145*t
Solvable: 1
-------------------------------------------------
Ending with final polynomial:
P : t^39 - 14781/1517*t^37 + 110853327/2529905*t^35 - 11796566093/97798899*t^33 + 1730387842513252/7612580353673*t^31 - 90709297733300428/291979291629587*t^29 + 864455535368955432604/2715800073961143717*t^27 - 28598377181097561437028468/114750097013952658553575*t^25 + 1317751195800797323139666235702/8747643165579280741175155829*t^23 - 3949536596798674474668812998245478/55996706561365351426259102950413*t^21 + 7078432311717584834357735360763643106/277362353637787607585961576742529001*t^19 - 34450244058808202119683936995639794/4866006204171712413788799591974193*t^17 + 235892972556644361184651555070883772/158860790783252964097222574914451595*t^15 - 2441075087659680694111346551221956/10590719385550197606481504994296773*t^13 + 2990096828362790833089012743071172/116497913241052173671296554937264503*t^11 - 1929837664080407985935549240228636/984936902856168377402779964469599889*t^9 + 2127721989736757259628890392309531/22215799031089131179196036976369864163*t^7 - 383765915316134443936486543434521/142815850914144414723403094848091983905*t^5 + 9131678489441746988055623894707/257068531645459946502125570726565571029*t^3 - 276219708581357823053539811719/1970858742615192923182962708903669377889*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: 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
-------------------------------------------------
The nodes are:
| (0.96020815213483003085 - 4.5441821334485922967e-881j)  +/-  (6.77e-242, 6.77e-242j)
| (0.97957230078926328156 - 1.761833994133342967e-881j)  +/-  (8.5e-242, 8.5e-242j)
| (-0.90315590361481790164 + 1.3398699611119719303e-880j)  +/-  (1.92e-242, 1.92e-242j)
| (0.99240684384358440319 + 3.0010298877378026681e-895j)  +/-  (7.65e-242, 7.65e-242j)
| (0.86577354268533519166 - 1.0971903350299907475e-897j)  +/-  (8.77e-243, 8.77e-243j)
| (0.82271465653714282498 + 3.1065965810625568032e-900j)  +/-  (2.35e-243, 2.35e-243j)
| (-0.99873801208031452959 + 1.1491213666065507189e-900j)  +/-  (3.37e-242, 3.37e-242j)
| (-0.93466400016551930719 - 9.0145454699789551452e-926j)  +/-  (4.07e-242, 4.07e-242j)
| (-0.96020815213483003085 + 1.5037602521694501031e-942j)  +/-  (6.77e-242, 6.77e-242j)
| (0.99873801208031452959 + 1.5540264672378993135e-960j)  +/-  (2.98e-242, 2.98e-242j)
| (0.90315590361481790164 - 1.0144163127704645591e-963j)  +/-  (1.91e-242, 1.91e-242j)
| (-0.97957230078926328156 + 8.8231615603927121826e-965j)  +/-  (8.39e-242, 8.39e-242j)
| (-0.86577354268533519166 + 1.1907310322913880112e-974j)  +/-  (7.98e-243, 7.98e-243j)
| (-0.82271465653714282498 - 7.2229196770754543513e-980j)  +/-  (2.61e-243, 2.61e-243j)
| (-0.99240684384358440319 + 5.1512912764832893781e-989j)  +/-  (7.65e-242, 7.65e-242j)
| (0.77432885900953476165 + 8.0217899175305484532e-997j)  +/-  (6.49e-244, 6.49e-244j)
| (0.93466400016551930719 + 1.4778094796680312233e-1000j)  +/-  (4.63e-242, 4.63e-242j)
| (-0.31656409996362983199 + 6.1150312356801134698e-1011j)  +/-  (1.58e-250, 1.58e-250j)
| (-0.77432885900953476165 + 2.0602224542232551444e-1005j)  +/-  (7e-244, 7e-244j)
| (-0.72096617733522937862 - 1.2410518696751382895e-1007j)  +/-  (1.31e-244, 1.31e-244j)
| (0.23922492831824141373 + 3.4778704872567397413e-1017j)  +/-  (8.84e-252, 8.84e-252j)
| (0.72096617733522937862 + 1.055601171046597601e-1009j)  +/-  (1.32e-244, 1.32e-244j)
| (0.16035864564022537587 - 1.1492890447730335391e-1019j)  +/-  (4.25e-253, 4.25e-253j)
| (-0.60054530466168102347 + 1.1071290307161347113e-1011j)  +/-  (3.1e-246, 3.1e-246j)
| (-0.5342756325305535152 - 7.3130136547053417116e-1014j)  +/-  (2.9e-247, 2.9e-247j)
| (-0.080451922744011330028 + 4.2399603136563819819e-1021j)  +/-  (2.57e-254, 2.57e-254j)
| (0.66292306574490784534 + 1.5080225883722868593e-1010j)  +/-  (2.2e-245, 2.2e-245j)
| (0.46457074137596094572 - 1.70967677303369032e-1014j)  +/-  (2.78e-248, 2.78e-248j)
| (-0.16035864564022537587 - 5.4716655427612654238e-1021j)  +/-  (4.05e-253, 4.05e-253j)
| (-0.66292306574490784534 + 4.9563990163193709379e-1013j)  +/-  (2.04e-245, 2.04e-245j)
| (-0.23922492831824141373 - 3.4511201627537999778e-1019j)  +/-  (9.65e-252, 9.65e-252j)
| (0.3918512308715201738 - 7.3359846617130184682e-1017j)  +/-  (2.2e-249, 2.2e-249j)
| (0.60054530466168102347 - 3.5965343066365721068e-1013j)  +/-  (2.88e-246, 2.88e-246j)
| (5.6152980869526963883e-1026 - 5.4150623239179902887e-1027j)  +/-  (2.2e-1024, 2.2e-1024j)
| (-0.46457074137596094572 - 1.8327111785847298617e-1019j)  +/-  (2.73e-248, 2.73e-248j)
| (-0.3918512308715201738 - 1.0957013944832580489e-1020j)  +/-  (2.13e-249, 2.13e-249j)
| (0.080451922744011330028 - 8.0402848886038219222e-1024j)  +/-  (2.57e-254, 2.57e-254j)
| (0.5342756325305535152 - 4.5003963339177841622e-1017j)  +/-  (2.84e-247, 2.84e-247j)
| (0.31656409996362983199 - 9.920452912020164803e-1022j)  +/-  (1.41e-250, 1.41e-250j)
-------------------------------------------------
The weights are:
| (0.022508695752204271122 - 1.2228018176484094877e-881j)  +/-  (2.26e-78, 8.65e-195j)
| (0.016153414369091354278 + 4.0177029683481800719e-881j)  +/-  (1.46e-78, 5.58e-195j)
| (0.034462352862880984706 + 1.1788684311610706103e-881j)  +/-  (7.65e-80, 2.93e-196j)
| (0.0094992054617100444906 + 1.8948228098872269281e-883j)  +/-  (5.57e-79, 2.13e-195j)
| (0.040270023249514782734 - 1.6359445467787307089e-881j)  +/-  (6.17e-80, 2.36e-196j)
| (0.045785973087922299093 + 1.3645252231685501016e-881j)  +/-  (1.86e-80, 7.12e-197j)
| (0.0033981531196347042004 + 4.6977418578958931566e-882j)  +/-  (1e-80, 3.85e-197j)
| (0.028544238117114997899 + 1.205346213833211524e-880j)  +/-  (3.39e-80, 1.3e-196j)
| (0.022508695752204271122 - 5.1872912370313979593e-881j)  +/-  (1.41e-80, 5.4e-197j)
| (0.0033981531196347042004 + 6.8189336126567342207e-883j)  +/-  (1.9e-80, 7.26e-197j)
| (0.034462352862880984706 + 2.2378568454002532986e-881j)  +/-  (2.87e-81, 1.1e-197j)
| (0.016153414369091354278 + 2.7988333808726384428e-881j)  +/-  (5.9e-81, 2.26e-197j)
| (0.040270023249514782734 - 1.4446369654410142575e-880j)  +/-  (3.7e-82, 1.42e-198j)
| (0.045785973087922299093 + 7.6591864776894440099e-881j)  +/-  (5.53e-83, 2.12e-199j)
| (0.0094992054617100444906 - 1.4759435981018111492e-881j)  +/-  (2.67e-81, 1.02e-197j)
| (0.0509262255062443251 - 1.2245312395556990953e-881j)  +/-  (9.83e-84, 3.76e-200j)
| (0.028544238117114997899 - 4.2116733889172595188e-881j)  +/-  (9.3e-82, 3.56e-198j)
| (0.076402861939816253641 + 1.9086742108013374958e-881j)  +/-  (5.36e-87, 2.05e-203j)
| (0.0509262255062443251 - 5.3617212149782130515e-881j)  +/-  (1.34e-84, 5.14e-201j)
| (0.055752201033481407359 + 4.1849265279482003811e-881j)  +/-  (1.62e-85, 6.19e-202j)
| (0.078186910685741706047 - 1.2250740814329106858e-881j)  +/-  (2.48e-88, 9.48e-205j)
| (0.055752201033481407359 + 1.1484101747614697033e-881j)  +/-  (2.18e-86, 8.36e-203j)
| (0.07946568358535507086 + 1.2829628630301882075e-881j)  +/-  (1.87e-88, 7.17e-205j)
| (0.06440235226192880107 + 2.9567408696194698477e-881j)  +/-  (1.21e-87, 4.65e-204j)
| (0.068059780498133280356 - 2.5931645029121965373e-881j)  +/-  (3.67e-88, 1.41e-204j)
| (0.080266216020850392581 - 1.5229771625453179108e-881j)  +/-  (4.59e-90, 1.76e-206j)
| (0.060277411503208184145 - 1.1083063164196044446e-881j)  +/-  (5.33e-89, 2.04e-205j)
| (0.071281424764929392464 + 1.1121909369891187308e-881j)  +/-  (1.97e-90, 7.53e-207j)
| (0.07946568358535507086 + 1.6315865330423338974e-881j)  +/-  (2.41e-90, 9.22e-207j)
| (0.060277411503208184145 - 3.4558858048126273217e-881j)  +/-  (5.66e-89, 2.17e-205j)
| (0.078186910685741706047 - 1.7583059167139724594e-881j)  +/-  (1.8e-90, 6.88e-207j)
| (0.074084074533738661446 - 1.1394839939375607132e-881j)  +/-  (2.04e-91, 7.83e-208j)
| (0.06440235226192880107 + 1.0927505196438217882e-881j)  +/-  (5.63e-91, 2.16e-207j)
| (0.08054560329299817282 + 1.429920912312901655e-881j)  +/-  (1.78e-91, 6.81e-208j)
| (0.071281424764929392464 + 2.3139645471218158553e-881j)  +/-  (2.94e-91, 1.12e-207j)
| (0.074084074533738661446 - 2.0907256612136222817e-881j)  +/-  (2.21e-91, 8.48e-208j)
| (0.080266216020850392581 - 1.3506879425176251536e-881j)  +/-  (2.35e-92, 9.03e-209j)
| (0.068059780498133280356 - 1.0956533071202829584e-881j)  +/-  (5.12e-93, 2.02e-209j)
| (0.076402861939816253641 + 1.177066076789445748e-881j)  +/-  (6.51e-93, 2.45e-209j)
