Starting with polynomial:
P : -1/5040*t^7 + 7/720*t^6 - 7/40*t^5 + 35/24*t^4 - 35/6*t^3 + 21/2*t^2 - 7*t + 1
Extension levels are: 7 15
-------------------------------------------------
Trying to find an order 15 Kronrod extension for:
P1 : -1/5040*t^7 + 7/720*t^6 - 7/40*t^5 + 35/24*t^4 - 35/6*t^3 + 21/2*t^2 - 7*t + 1
Solvable: 1
-------------------------------------------------
Ending with final polynomial:
P : -1/5040*t^22 + 20537853706984048056173384256728419/272049232864620213787750558614030240*t^21 - 56300057947779891974744925925866459/4318241791501908155361119978000480*t^20 + 3514996909267063911886297040692665695/2590945074901144893216671986800288*t^19 - 246703740692178869049659769733530041555/2590945074901144893216671986800288*t^18 + 2064897990882605584281502545187025962099/431824179150190815536111997800048*t^17 - 230435840353488967221891918594314198150423/1295472537450572446608335993400144*t^16 + 589543718147106850034264282951152443567649/117770230677324767873485090309104*t^15 - 46604409195673882408038078554309072639259225/431824179150190815536111997800048*t^14 + 387366844971787692023000880529594748386706825/215912089575095407768055998900024*t^13 - 4973336693655201865516194683316418731529029755/215912089575095407768055998900024*t^12 + 12297123459637092302062258568020626912797373555/53978022393773851942013999725006*t^11 - 8461695757226381708801212662590233734504499965/4907092944888531994728545429546*t^10 + 24244311016921840445657373481511486283698838375/2453546472444265997364272714773*t^9 - 103547790753039606423150391591061974866608816625/2453546472444265997364272714773*t^8 + 322596237766683144680129243812681049886286014600/2453546472444265997364272714773*t^7 - 711875009607663940188915065885805238835067923400/2453546472444265997364272714773*t^6 + 1068544127658935656117491535243490731957330261200/2453546472444265997364272714773*t^5 - 1030085044444491435106697780010302169005427510000/2453546472444265997364272714773*t^4 + 585257625530959288123976254872939357628964040000/2453546472444265997364272714773*t^3 - 170421464738964179177823246665326840308063528000/2453546472444265997364272714773*t^2 + 19554189481592882480117430428299376101810992000/2453546472444265997364272714773*t - 456347372365474366645657007685199489903056000/2453546472444265997364272714773
-------------------------------------------------
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:   22 out of 22
Indefinite weights: 0 out of 22
Negative weights:   0 out of 22
Extension rule has valid weights: 1
-------------------------------------------------
The nodes are:
| (61.823305604406539676 - 2.787536143759409961e-285j)  +/-  (2.16e-119, 2.16e-119j)
| (22.550845316541610067 + 6.2275478941987872051e-282j)  +/-  (3.02e-116, 3.02e-116j)
| (37.072234090071209445 + 7.662547325121689702e-289j)  +/-  (3.73e-117, 3.73e-117j)
| (43.571435409296839077 - 2.4046617924666750625e-291j)  +/-  (1.23e-117, 1.23e-117j)
| (51.457201277244999156 + 2.8228399727396656934e-293j)  +/-  (2.34e-118, 2.34e-118j)
| (2.5678767449507462069 - 4.0631792027547905946e-296j)  +/-  (2.12e-121, 2.12e-121j)
| (31.533552477785297315 - 6.92348696244339233e-292j)  +/-  (7.89e-117, 7.89e-117j)
| (6.4010557721913196561 - 5.0263801139186375006e-298j)  +/-  (4.09e-119, 4.09e-119j)
| (15.550695464016329182 + 3.0544026743310351795e-302j)  +/-  (9.95e-117, 9.95e-117j)
| (8.1821534445628607911 - 4.4608137288844535472e-311j)  +/-  (1.78e-118, 1.78e-118j)
| (0.19304367656036241384 + 1.6565176417783387509e-324j)  +/-  (4.66e-126, 4.66e-126j)
| (4.9003530845264845681 - 2.7216375855441286548e-315j)  +/-  (9.2e-120, 9.2e-120j)
| (26.734410933433716354 - 1.6184166359500438802e-322j)  +/-  (1.6e-116, 1.6e-116j)
| (10.284293036021601441 - 6.3744226605476709824e-344j)  +/-  (6.16e-118, 6.16e-118j)
| (19.395727862262540312 - 8.0478959154357088459e-357j)  +/-  (9.21e-116, 9.21e-116j)
| (1.0266648953391919503 + 6.7912928875234987062e-382j)  +/-  (1.71e-123, 1.71e-123j)
| (1.701983566347955091 - 7.9452800178456406891e-380j)  +/-  (2.21e-122, 2.21e-122j)
| (12.734180291797813758 + 4.8597700924463933159e-373j)  +/-  (2.44e-117, 2.44e-117j)
| (0.030757103100622206566 + 3.6778809272054682784e-391j)  +/-  (1.58e-127, 1.58e-127j)
| (18.616143398534321139 + 1.7101298264885990311e-384j)  +/-  (7.87e-116, 7.87e-116j)
| (3.6321318672029835931 + 2.3090991166106232922e-405j)  +/-  (1.62e-120, 1.62e-120j)
| (0.52543370263227082813 + 2.3866201427358840452e-409j)  +/-  (1.11e-124, 1.11e-124j)
-------------------------------------------------
The weights are:
| (1.7681750092402404621e-26 + 4.9906916684738897976e-303j)  +/-  (2.68e-46, 1.8e-102j)
| (6.2597346824036299928e-10 - 3.4714907118816041637e-291j)  +/-  (9.34e-38, 6.28e-94j)
| (4.7400103913318952643e-16 - 1.5288035036470713387e-296j)  +/-  (3.84e-42, 2.58e-98j)
| (8.4724948374388843045e-19 + 2.3339687502991469053e-298j)  +/-  (1.05e-43, 7.05e-100j)
| (3.967078318169093128e-22 - 1.9622992085251248486e-300j)  +/-  (2.3e-45, 1.55e-101j)
| (0.073999655271627012891 - 1.4807456294916891383e-287j)  +/-  (3.28e-26, 2.21e-82j)
| (1.0381472648300117068e-13 + 7.4569947850316848594e-295j)  +/-  (1.26e-41, 8.48e-98j)
| (0.0027101120699230565999 + 1.8143674297568489882e-288j)  +/-  (3.91e-33, 2.63e-89j)
| (5.2934997104794653134e-07 + 3.3335462177097594685e-290j)  +/-  (1.82e-38, 1.22e-94j)
| (0.00054136975081888066599 - 6.7710894044304329446e-289j)  +/-  (4.29e-35, 2.88e-91j)
| (0.20292083607405529599 - 2.1895476241491762155e-287j)  +/-  (3.65e-30, 2.45e-86j)
| (0.010251948680431970392 - 4.2394144966690286846e-288j)  +/-  (7.79e-33, 5.24e-89j)
| (1.0975023151937135834e-11 - 3.8264550452607162676e-293j)  +/-  (1.97e-41, 1.33e-97j)
| (7.7634661558465586519e-05 + 2.3202879855255538958e-289j)  +/-  (4.43e-37, 2.98e-93j)
| (3.7895075488528211568e-09 + 3.4158419497339098099e-290j)  +/-  (4.54e-40, 3.05e-96j)
| (0.20983024094826481685 - 2.8025502934408912598e-287j)  +/-  (1.5e-33, 1.01e-89j)
| (0.14004466803638127446 + 2.2243684087202878656e-287j)  +/-  (3.77e-34, 2.53e-90j)
| (7.7572071601464013661e-06 - 7.9702975833730891819e-290j)  +/-  (4.35e-39, 2.92e-95j)
| (0.081945181533452551002 + 8.3351987210992990322e-288j)  +/-  (8.15e-35, 5.47e-91j)
| (2.1113696725308414214e-08 - 4.2523725920111567884e-290j)  +/-  (5.91e-40, 3.98e-96j)
| (0.030800395644438506472 + 8.5113940940055140242e-288j)  +/-  (2.09e-36, 1.4e-92j)
| (0.24686964523165991961 + 2.856652762201139897e-287j)  +/-  (2.32e-35, 1.55e-91j)
Starting with polynomial:
P : -1/5040*t^7 + 7/720*t^6 - 7/40*t^5 + 35/24*t^4 - 35/6*t^3 + 21/2*t^2 - 7*t + 1
Extension levels are: 7 15
-------------------------------------------------
Trying to find an order 15 Kronrod extension for:
P1 : -1/5040*t^7 + 7/720*t^6 - 7/40*t^5 + 35/24*t^4 - 35/6*t^3 + 21/2*t^2 - 7*t + 1
Solvable: 1
-------------------------------------------------
Ending with final polynomial:
P : -1/5040*t^22 + 20537853706984048056173384256728419/272049232864620213787750558614030240*t^21 - 56300057947779891974744925925866459/4318241791501908155361119978000480*t^20 + 3514996909267063911886297040692665695/2590945074901144893216671986800288*t^19 - 246703740692178869049659769733530041555/2590945074901144893216671986800288*t^18 + 2064897990882605584281502545187025962099/431824179150190815536111997800048*t^17 - 230435840353488967221891918594314198150423/1295472537450572446608335993400144*t^16 + 589543718147106850034264282951152443567649/117770230677324767873485090309104*t^15 - 46604409195673882408038078554309072639259225/431824179150190815536111997800048*t^14 + 387366844971787692023000880529594748386706825/215912089575095407768055998900024*t^13 - 4973336693655201865516194683316418731529029755/215912089575095407768055998900024*t^12 + 12297123459637092302062258568020626912797373555/53978022393773851942013999725006*t^11 - 8461695757226381708801212662590233734504499965/4907092944888531994728545429546*t^10 + 24244311016921840445657373481511486283698838375/2453546472444265997364272714773*t^9 - 103547790753039606423150391591061974866608816625/2453546472444265997364272714773*t^8 + 322596237766683144680129243812681049886286014600/2453546472444265997364272714773*t^7 - 711875009607663940188915065885805238835067923400/2453546472444265997364272714773*t^6 + 1068544127658935656117491535243490731957330261200/2453546472444265997364272714773*t^5 - 1030085044444491435106697780010302169005427510000/2453546472444265997364272714773*t^4 + 585257625530959288123976254872939357628964040000/2453546472444265997364272714773*t^3 - 170421464738964179177823246665326840308063528000/2453546472444265997364272714773*t^2 + 19554189481592882480117430428299376101810992000/2453546472444265997364272714773*t - 456347372365474366645657007685199489903056000/2453546472444265997364272714773
-------------------------------------------------
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:   22 out of 22
Indefinite weights: 0 out of 22
Negative weights:   0 out of 22
Extension rule has valid weights: 1
-------------------------------------------------
The nodes are:
| (61.823305604406539676 - 2.787536143759409961e-285j)  +/-  (2.16e-119, 2.16e-119j)
| (22.550845316541610067 + 6.2275478941987872051e-282j)  +/-  (3.02e-116, 3.02e-116j)
| (37.072234090071209445 + 7.662547325121689702e-289j)  +/-  (3.73e-117, 3.73e-117j)
| (43.571435409296839077 - 2.4046617924666750625e-291j)  +/-  (1.23e-117, 1.23e-117j)
| (51.457201277244999156 + 2.8228399727396656934e-293j)  +/-  (2.34e-118, 2.34e-118j)
| (2.5678767449507462069 - 4.0631792027547905946e-296j)  +/-  (2.12e-121, 2.12e-121j)
| (31.533552477785297315 - 6.92348696244339233e-292j)  +/-  (7.89e-117, 7.89e-117j)
| (6.4010557721913196561 - 5.0263801139186375006e-298j)  +/-  (4.09e-119, 4.09e-119j)
| (15.550695464016329182 + 3.0544026743310351795e-302j)  +/-  (9.95e-117, 9.95e-117j)
| (8.1821534445628607911 - 4.4608137288844535472e-311j)  +/-  (1.78e-118, 1.78e-118j)
| (0.19304367656036241384 + 1.6565176417783387509e-324j)  +/-  (4.66e-126, 4.66e-126j)
| (4.9003530845264845681 - 2.7216375855441286548e-315j)  +/-  (9.2e-120, 9.2e-120j)
| (26.734410933433716354 - 1.6184166359500438802e-322j)  +/-  (1.6e-116, 1.6e-116j)
| (10.284293036021601441 - 6.3744226605476709824e-344j)  +/-  (6.16e-118, 6.16e-118j)
| (19.395727862262540312 - 8.0478959154357088459e-357j)  +/-  (9.21e-116, 9.21e-116j)
| (1.0266648953391919503 + 6.7912928875234987062e-382j)  +/-  (1.71e-123, 1.71e-123j)
| (1.701983566347955091 - 7.9452800178456406891e-380j)  +/-  (2.21e-122, 2.21e-122j)
| (12.734180291797813758 + 4.8597700924463933159e-373j)  +/-  (2.44e-117, 2.44e-117j)
| (0.030757103100622206566 + 3.6778809272054682784e-391j)  +/-  (1.58e-127, 1.58e-127j)
| (18.616143398534321139 + 1.7101298264885990311e-384j)  +/-  (7.87e-116, 7.87e-116j)
| (3.6321318672029835931 + 2.3090991166106232922e-405j)  +/-  (1.62e-120, 1.62e-120j)
| (0.52543370263227082813 + 2.3866201427358840452e-409j)  +/-  (1.11e-124, 1.11e-124j)
-------------------------------------------------
The weights are:
| (1.7681750092402404621e-26 + 4.9906916684738897976e-303j)  +/-  (2.68e-46, 1.8e-102j)
| (6.2597346824036299928e-10 - 3.4714907118816041637e-291j)  +/-  (9.34e-38, 6.28e-94j)
| (4.7400103913318952643e-16 - 1.5288035036470713387e-296j)  +/-  (3.84e-42, 2.58e-98j)
| (8.4724948374388843045e-19 + 2.3339687502991469053e-298j)  +/-  (1.05e-43, 7.05e-100j)
| (3.967078318169093128e-22 - 1.9622992085251248486e-300j)  +/-  (2.3e-45, 1.55e-101j)
| (0.073999655271627012891 - 1.4807456294916891383e-287j)  +/-  (3.28e-26, 2.21e-82j)
| (1.0381472648300117068e-13 + 7.4569947850316848594e-295j)  +/-  (1.26e-41, 8.48e-98j)
| (0.0027101120699230565999 + 1.8143674297568489882e-288j)  +/-  (3.91e-33, 2.63e-89j)
| (5.2934997104794653134e-07 + 3.3335462177097594685e-290j)  +/-  (1.82e-38, 1.22e-94j)
| (0.00054136975081888066599 - 6.7710894044304329446e-289j)  +/-  (4.29e-35, 2.88e-91j)
| (0.20292083607405529599 - 2.1895476241491762155e-287j)  +/-  (3.65e-30, 2.45e-86j)
| (0.010251948680431970392 - 4.2394144966690286846e-288j)  +/-  (7.79e-33, 5.24e-89j)
| (1.0975023151937135834e-11 - 3.8264550452607162676e-293j)  +/-  (1.97e-41, 1.33e-97j)
| (7.7634661558465586519e-05 + 2.3202879855255538958e-289j)  +/-  (4.43e-37, 2.98e-93j)
| (3.7895075488528211568e-09 + 3.4158419497339098099e-290j)  +/-  (4.54e-40, 3.05e-96j)
| (0.20983024094826481685 - 2.8025502934408912598e-287j)  +/-  (1.5e-33, 1.01e-89j)
| (0.14004466803638127446 + 2.2243684087202878656e-287j)  +/-  (3.77e-34, 2.53e-90j)
| (7.7572071601464013661e-06 - 7.9702975833730891819e-290j)  +/-  (4.35e-39, 2.92e-95j)
| (0.081945181533452551002 + 8.3351987210992990322e-288j)  +/-  (8.15e-35, 5.47e-91j)
| (2.1113696725308414214e-08 - 4.2523725920111567884e-290j)  +/-  (5.91e-40, 3.98e-96j)
| (0.030800395644438506472 + 8.5113940940055140242e-288j)  +/-  (2.09e-36, 1.4e-92j)
| (0.24686964523165991961 + 2.856652762201139897e-287j)  +/-  (2.32e-35, 1.55e-91j)
