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 26
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Trying to find an order 26 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
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Ending with final polynomial:
P : 4096*t^38 - 2084325822728699377664/1939697391247873*t^36 + 12764196228679412014080/102089336381467*t^34 - 281825365093423316958481920/32974855651213841*t^32 + 12640679227585047551277657600/32974855651213841*t^30 - 23154227386664309778522113280/1939697391247873*t^28 + 8783342126725957863077741028480/32974855651213841*t^26 - 142949014292397767002661465496000/32974855651213841*t^24 + 1711015887184879690601524248768000/32974855651213841*t^22 - 15077333705922418067686603814760000/32974855651213841*t^20 + 5119244626725911237598598798242000/1735518718484939*t^18 - 1404452150698008976619939897013000/102089336381467*t^16 + 4638434539961564790921164045103750/102089336381467*t^14 - 10513448405089607686213935851045625/102089336381467*t^12 + 31226164056501472867664544617053125/204178672762934*t^10 - 56665743681964077911362092742636875/408357345525868*t^8 + 112512516106672640463452188649533125/1633429382103472*t^6 - 50639498722059425888731565741071875/3266858764206944*t^4 + 7350088095763929378434773929853125/6533717528413888*t^2 - 188306128954750142537176209609375/13067435056827776
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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
Positive weights:   36 out of 38
Indefinite weights: 0 out of 38
Negative weights:   2 out of 38
Extension rule has valid weights: 0
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*** EXTENSION WITH INVALID WEIGHTS ***
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