Starting with polynomial:
P : t^3 - 3*t
Extension levels are: 3 20
-------------------------------------------------
Trying to find an order 20 Kronrod extension for:
P1 : t^3 - 3*t
Solvable: 1
-------------------------------------------------
Ending with final polynomial:
P : t^23 - 108850387/466119*t^21 + 3492043345/155373*t^19 - 60312139755/51791*t^17 + 1845365502470/51791*t^15 - 34442483318670/51791*t^13 + 391719784111110/51791*t^11 - 2637542954196150/51791*t^9 + 9887794220979675/51791*t^7 - 18448838678845575/51791*t^5 + 13826157508738575/51791*t^3 - 2510039001444975/51791*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:   23 out of 23
Indefinite weights: 0 out of 23
Negative weights:   0 out of 23
Extension rule has valid weights: 1
-------------------------------------------------
The nodes are:
| (-3.7735517795464091271 - 2.1145242234424503061e-369j)  +/-  (1.63e-122, 1.63e-122j)
| (7.0033476606809411206 + 1.1709309279174224573e-373j)  +/-  (2.1e-122, 2.1e-122j)
| (6.0930224485698685645 + 1.3621099037585654961e-376j)  +/-  (4.3e-122, 4.3e-122j)
| (2.3917677007532019761 - 2.4321142304305932086e-379j)  +/-  (1.04e-123, 1.04e-123j)
| (-8.0890746929034945807 - 4.1898480490058685333e-377j)  +/-  (4.14e-123, 4.14e-123j)
| (8.0890746929034945807 - 9.1201473284637140948e-386j)  +/-  (4.63e-123, 4.63e-123j)
| (-6.0930224485698685645 - 2.0634802474030246952e-384j)  +/-  (4.53e-122, 4.53e-122j)
| (-3.071631883971911224 + 2.2622167784267322709e-393j)  +/-  (5.39e-123, 5.39e-123j)
| (-7.0033476606809411206 - 2.018212574124602638e-398j)  +/-  (2.18e-122, 2.18e-122j)
| (4.5032847062465564958 - 4.3298513988197681405e-406j)  +/-  (3.62e-122, 3.62e-122j)
| (-5.2707607326550534535 - 2.0907072416143880259e-411j)  +/-  (5.29e-122, 5.29e-122j)
| (-0.50993263938559207645 + 5.3188698819940880624e-422j)  +/-  (2.61e-126, 2.61e-126j)
| (-2.3917677007532019761 + 3.5147600419940229967e-420j)  +/-  (1.23e-123, 1.23e-123j)
| (-1.7320508075688772935 + 1.8695015863428955013e-423j)  +/-  (1.82e-124, 1.82e-124j)
| (3.7735517795464091271 - 1.9585993297185663139e-425j)  +/-  (1.76e-122, 1.76e-122j)
| (1.097390394480852298 - 8.6254198374319616374e-426j)  +/-  (2.38e-125, 2.38e-125j)
| (3.071631883971911224 + 2.1158290575868393658e-426j)  +/-  (5.46e-123, 5.46e-123j)
| (2.0439056797591021982e-425 - 1.0977807065822496629e-425j)  +/-  (5.34e-424, 5.34e-424j)
| (-1.097390394480852298 + 3.551846210778675911e-425j)  +/-  (2.38e-125, 2.38e-125j)
| (-4.5032847062465564958 - 2.1999775247196280775e-427j)  +/-  (3.62e-122, 3.62e-122j)
| (1.7320508075688772935 - 1.4573442107500486409e-434j)  +/-  (1.81e-124, 1.81e-124j)
| (0.50993263938559207645 - 2.5485718167929806774e-437j)  +/-  (2.61e-126, 2.61e-126j)
| (5.2707607326550534535 - 1.1148362211310394118e-433j)  +/-  (5.42e-122, 5.42e-122j)
-------------------------------------------------
The weights are:
| (0.0002305912622569605921 - 1.0451694389359994289e-372j)  +/-  (4.63e-43, 3.28e-103j)
| (8.6941663855970540721e-12 - 4.786793268133176106e-378j)  +/-  (2.85e-49, 2.02e-109j)
| (2.9721548441947746391e-09 + 1.1094908768960975971e-376j)  +/-  (4.24e-48, 3.01e-108j)
| (0.015299987104727462419 - 9.9363256089449329262e-373j)  +/-  (7.31e-41, 5.18e-101j)
| (3.0754180585143364472e-15 - 1.94873265534841333e-379j)  +/-  (3.58e-52, 2.54e-112j)
| (3.0754180585143364472e-15 + 7.089322677323368421e-380j)  +/-  (2.86e-51, 2.03e-111j)
| (2.9721548441947746391e-09 - 4.7195560486497770654e-376j)  +/-  (6.81e-50, 4.83e-110j)
| (0.0024611269891439376996 + 2.7661968054059188632e-372j)  +/-  (2.4e-45, 1.7e-105j)
| (8.6941663855970540721e-12 + 1.5972139138965335839e-377j)  +/-  (3.5e-51, 2.48e-111j)
| (1.1756902744931743466e-05 + 1.1198438807153209322e-374j)  +/-  (4.39e-49, 3.12e-109j)
| (2.9283548821055862411e-07 + 8.3725341665219980837e-375j)  +/-  (3.65e-49, 2.59e-109j)
| (0.19263250755855154045 + 1.9549824565238717121e-371j)  +/-  (2.96e-44, 2.08e-104j)
| (0.015299987104727462419 - 4.4334438156916671529e-372j)  +/-  (2.05e-45, 1.45e-105j)
| (0.057764313554567933236 + 7.7942598283673399848e-372j)  +/-  (1.33e-44, 9.44e-105j)
| (0.0002305912622569605921 - 6.4606352550227469186e-374j)  +/-  (9.16e-49, 6.5e-109j)
| (0.13480533118065524373 - 7.1988977643228227112e-372j)  +/-  (7.99e-45, 5.63e-105j)
| (0.0024611269891439376996 + 2.8365179704856497748e-373j)  +/-  (5.35e-48, 3.78e-108j)
| (0.19358817926202338715 - 2.1231428856251430881e-371j)  +/-  (4.47e-45, 3.1e-105j)
| (0.13480533118065524373 - 1.3102877372028896021e-371j)  +/-  (1.7e-45, 1.19e-105j)
| (1.1756902744931743466e-05 - 1.2701584005071074579e-373j)  +/-  (3.17e-49, 2.23e-109j)
| (0.057764313554567933236 + 2.8901448908623192772e-372j)  +/-  (4.05e-47, 2.67e-107j)
| (0.19263250755855154045 + 1.4895159087889963268e-371j)  +/-  (3.07e-46, 2e-106j)
| (2.9283548821055862411e-07 - 1.3860019089076996859e-375j)  +/-  (7.7e-51, 5.61e-111j)
