T-136: Seventeen exact rational packings from SQUISH's third request

V3 C3 upper bound confirmed

2026-10-09 published · Chaoweeraprasit after Couzo, Xu, Goebel, Schadt, Ellsworth, Hajba, Levy · 17 cases, n=131 to 307

Seventeen complete rational source certificates by Nate Chaoweeraprasit, using SQUISH, reported on jlevy/squares#481, prove finite upper bounds at the exact sides they state: s(131)≤546262522801617822590053861036247525257980632054448711125685429647597444905863823/45713647219586261662645849733884420493261937951141483500332220381589307940237228, s(153)≤123797999524180008078530976954463155877532124256188212074430292658566758958161323/9617597300166052747813209874613658336103061290746859396882208758750786210512186, s(154)≤784162558492446266593660385683137819091796768322490163735346888314210507575675725/60679277154496515024381071712664165344389803410694160363187109568787250164584599, s(207)≤735531374822863515605402999283143325118010869312518967079087271050773613271161277/49412586952851805135714733794522095254473298746909591292001747563872946931057236, s(209)≤352086775394428731924221642717430604621536094874634535695725650032320439933977965/23556905311577298619235189039173243928057287546251527278924911938419541052151072, s(232)≤1114406289130974410117782886660181901248480109604626847722783024235385594726280057/70677745564963034331738560467960182867819656746924792855394670571264398270484380, s(236)≤50320092412194411351092950431375593124874735166028004482989966459031138777005556/3171976347778525974082487945502584792871670535146640434897907865344648863834385, s(237)≤985175957045048952983043545219609058238043896611796404750765221827457100311536267/61949105502245043847087036993442184322886619069992659024865961513616685288782651, s(259)≤341518036803803444006790647841670042984586128471540050420967157601697370040453146/20584066845374091244555983652288807088661645599927706951717180608041569765032899, s(263)≤432047778146841439029580692611188349728625751403534114235890133210701007973167612458309659642793497978693924904370413739637576535113305805473258454023835719181271711048486015594317660810620737576607410036454490449350514789375965798922408137/25819846521744160772224038706040075666707832377280732314567257517966255239622299571357684220252697011172510448203687628392777898509200720976473115105878476541217151532309155922966611211236819896892204567384190375033297252622850484642835750, s(269)≤564564911646728951775552019108871435401015878808547246372660532154424222542885997/33403216161756613117962569049021857533205635354720854135770446125559372407730671, s(270)≤161730688683764189720413661089911172609666557649301664556207086991163746546642589/9553029482827216570142998318928918813620116649281833748281870132253732451342836, s(292)≤3761323845345218139515171916971344444825061926100378742572376994966931648579540403209467016041816040337818900346425264425539321771370681685330920067362079436395820610782571906200300814877227551992417206915107675733654665670276860831914801/213816326056741634814067355276646187722839206218411265487734233051189296444092664982158379275294035512776959997090425431151515816435932969086410258658043702048010698581133434199424606616799121971830257866615621151317801149797139930258434, s(302)≤820999445009309740922029456921019877028889439831661589361637087272075109744743203/45937671990376526418357407123080370268809104789707150587775569201223938448317194, s(303)≤162263195772134120155792974649693427899481189466645405582211912387896660025441601/9058371171012706945350582640902165821875350160207702968863672420698760940328800, s(305)≤20660996865663684228769265396330188251261172861603842154544163047966189801381587/1150953769306329632110500736581956206891780101292689658665490428813909216741750 and s(307)≤60196283485579249701801076299725636673865869456384222766836544824201358530035066/3347797278057252711799171413359076616946062908168377655562490378685987266056665.

Each certificate gives a rational side and, for each unit square, a rational centre and the tangent of its half-angle, in SQUISH's JSON; each side is the exact fraction the source's summary.csv prints, and the issue's 15-digit displays are not roundings of it. The author reports that SQUISH's exact Fraction checker accepts all seventeen and David Ellsworth's check_packing.py each 50-digit export, and that each certificate was drawn from a 60-digit contact solution with clearance 1e-32, about 1e-14 at 263 and 292.

At every count squares touch the closed box, a least wall clearance of exactly 0, which the record's closed-box convention admits; no two squares meet, and the bound also holds if s(n) is read as an open-box infimum.

All 51 retained jobs, the seventeen positives with their duplicate-square and outside-container controls, were decided again here on 10 October 2026 by both maintained exact routes, from exact facts derived from the pinned certificates, and equal their retained rows. A third exact route, half-extent containment and exact intersection area, decided the seventeen with six controls each and found each fact to be the packing its pinned upstream file states. No route here is the source's code, so the replay is independently re-implemented. The 10 October review found no blocking defect.

Each side is below the ceiling its case holds, and below every other report pending at its count except at 209, 237, 270 and 305, where Francisco Couzo's later certificates of issue 488 (T-140) are smaller, and at 153, 236, 263, 269, 292, 302 and 303, where Evan Daniel's later regularized certificates (T-146) are smaller; the case records are unchanged until a house is adopted, so each is pending adoption.

Credit Nate Chaoweeraprasit (https://github.com/itsnaka/squish-certs), using SQUISH and its Mondrian composition method, after Francisco Couzo, Ryan Xu, Frits Göbel, Thomas Schadt, David Ellsworth and Károly Hajba, whose packings supplied pieces, as the issue's credit line names them. Per count, the issue lists the pieces: the Kingbird catalogue's packing of 5 and former records at 11, 50, 152, 202 and 241, Francisco Couzo's packings of 182 and 180, Ryan Xu's of 123, 129 and 175, and SQUISH's own earlier packings. The source states that the solver, its verification and the issue were written with Claude Opus 5.5 under the author's direction.

Significance, composition and next rung
Significance
Smaller finite construction sides at n=131, 153, 154, 207, 209, 232, 236, 237, 259, 263, 269, 270, 292, 302, 303, 305 and 307, 1.68e-04 to 1.12e-02 below the case ceilings; no lower bound or optimum.
Next rung
V4 and C4 need a retained human oversight record: two accepted adversarial reviews by distinct AI reviewers are retained, the 10 October review and the 11 October final review (docs/project/reviews/review-2026-10-11-final-upper-bounds.md). Separately, once jlevy/squares#403 lands and private-worker custody is on file (RI-5), adopt this entry as the house at 131, 154, 207, 232, 259 and 307, the six counts where it is the smallest, with each earlier house kept as history. At 153, 236, 263, 269, 292, 302 and 303 the house recommendation goes to T-146, whose 11 October review accepted it.
Novelty
previously-published Present in an identified source

The cases

This result concerns 17 cases, too many to draw one by one. Each is listed with the film’s bounds, the proved lower bound and the best known side, and links to its case record, where its packing and number line are drawn.

nProved lowerBest knownGapStatusRecords
13111.46585611.9511510.48529394…open=frontier n-131.md
15312.38486412.8796800.49481504…frontier n-153.md
15412.42686012.9265630.49970180…frontier n-154.md
20714.40143814.8879930.48655348…frontier n-207.md
20914.47318814.9496180.47642933…frontier n-209.md
23215.23940215.7781750.53877162…frontier n-232.md
23615.37447415.8678010.49332605…frontier n-236.md
23715.40805115.9036770.49562471…frontier n-237.md
25916.09647316.6025690.50609453…open≈frontier n-259.md
26316.22418516.7404200.51623448…open=frontier n-263.md
26916.41383016.9059680.49213659…open≈frontier n-269.md
27016.44521816.9378080.49258850…open=frontier n-270.md
29217.09066017.5972500.50658936…frontier n-292.md
30217.38934517.8813070.49196046…frontier n-302.md
30317.41892417.9203130.50138805…frontier n-303.md
30517.47792617.9529600.47503261…open≈frontier n-305.md
30717.53672517.9810310.44430551…frontier n-307.md

Results on these cases

23 results in the register on these cases, oldest first
  1. 2005 published T-007 · 17 of these cases

    s(n)≥min(⌈n⌉,n−2⌊n⌋+1+1) for 4≤n≤324

    lower bound incomplete

    Nagamochi · Nagamochi 2005 · source · register

  2. 2026-09-04 published T-085 · 17 of these cases

    Nagamochi 2005, Lemma 1 is false for every container with a>3 and b>2

    correction confirmed

    Karakuş; chelokot · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register

  3. 2026-09-27 published T-056 · 15 of these cases

    Smaller packings for 49 counts from n=68 to 307, each certified two independent ways

    upper bound confirmed superseded by T-098, T-113, T-116, T-117, T-119, T-125 and T-127

    Couzo · franciscouzo square-packing 2026-09-27 · packet · register

  4. 2026-09-29 published T-083 · 17 of these cases

    s(n)≥1/2+n−⌊n⌋+1/4 for every nonsquare 8≤n≤324

    lower bound confirmed

    Karakuş · Karakuş 2026 · source · register

  5. 2026-10-03 published T-092 · cases 209, 263, 303

    Smaller packings again at seven counts from n=208 to 306, each certified two independent ways

    upper bound confirmed superseded by T-113, T-116 and T-127

    Couzo · franciscouzo square-packing 2026-10-03 · packet · register

  6. 2026-10-05 published T-098 · 14 of these cases

    Exact optima of 48 known-best packings: s(n) ≤ S', 3.5e-13 to 5.0e-11 below each printed side

    upper bound confirmed

    Daniel after Couzo, de Winter, Ellsworth, Levy · evand exact optima 2026-10-05 · packet · register

  7. 2026-10-05 published T-101 · cases 153, 232

    Exact certificates of 77 catalogue packings: s(n) ≤ S', 1.2e-16 to 9.8e-15 above each side

    upper bound confirmed

    Daniel after Couzo, de Winter, Ellsworth, Levy · evand exact optima 2026-10-05 · packet · register

  8. 2026-10-07 published T-113 · cases 154, 209, 303

    s(n)≤Sn at ten counts, n=108 to 303, from new SQUISH rational packings

    upper bound confirmed

    Chaoweeraprasit after Ellsworth · SQUISH ten packings 2026-10-07 · packet · register

  9. 2026-10-07 published T-114 · case 153

    s(153)≤7250614903299225/562949953421312, from a SQUISH rational packing

    upper bound confirmed superseded by T-127

    Chaoweeraprasit after Ellsworth · SQUISH n153 2026-10-07 · packet · packet · register

  10. 2026-10-07 published T-115 · cases 154, 237, 263

    s(n)≤Sn at twelve counts, from the SQUISH update’s new and smaller rational packings

    upper bound confirmed on these cases, superseded by T-116 and T-127

    Chaoweeraprasit after Couzo and Ellsworth · SQUISH update 2026-10-07 · packet · register

  11. 2026-10-07 published T-116 · cases 207, 236, 263, 302

    s(n)≤Sn at nine counts, from the second SQUISH update’s new rational packings

    upper bound confirmed

    Chaoweeraprasit after Ellsworth, Couzo and SQUISH · SQUISH second update 2026-10-07 · packet · register

  12. 2026-10-07 published T-117 · case 292

    Exact rational ceiling refinements at n=105, 292

    upper bound confirmed

    Rehwaldt after Couzo and earlier contributors · Rehwaldt Couzo refinements 2026-10-07 · packet · register

  13. 2026-10-07 published T-119 · case 270

    Three exact feasible upper bounds at n=266,270,272 from new source arrangements

    upper bound confirmed

    Daniel after Levy, Ellsworth, Couzo, Stead · Daniel new arrangements 2026-10-07 · packet · register

  14. 2026-10-07 published T-129 · case 292

    Three dated Daniel certificate reports with historical source custody

    upper bound recorded superseded by T-117

    Daniel after Couzo, Levy · Daniel dated certificates 105 and 130 2026-10-07 · Daniel dated certificate 292 2026-10-07 · packet · packet · packet · register

  15. 2026-10-08 published T-125 · cases 131, 153, 236, 263

    Complete rational construction reports at 25 counts

    upper bound confirmed

    ry-xu · ry-xu square packing 2026 · packet · register

  16. 2026-10-08 published T-127 · 6 of these cases

    Fourteen rational refinements, seventeen complete source cases

    upper bound confirmed

    Gupta after Chaoweeraprasit, Daniel · Gupta rational refinements 2026-10-08 · packet · register

  17. 2026-10-08 published T-128 · case 131

    Eight complete rational refinements from Francisco Couzo

    upper bound confirmed

    Couzo after Xu, Chaoweeraprasit, Gupta, Ellsworth, Daniel, Levy · Couzo exact refinements 2026-10-08 · packet · register

  18. 2026-10-08 published T-130 · case 270

    Five follow-up rational refinements from Francisco Couzo

    upper bound confirmed

    Couzo after Xu, Daniel, Ellsworth, Levy · Couzo follow-up refinements 2026-10-08 · packet · register

  19. 2026-10-09 published T-134 · cases 237, 263, 270, 303

    Six exact rational certificates from Francisco Couzo

    upper bound confirmed

    Couzo after Mishapolk, Chaoweeraprasit, Gupta, Xu, Daniel, Ellsworth, Levy · Couzo exact certificates 2026-10-09 · packet · register

  20. 2026-10-09 published T-136 this result · 17 of these cases

    Seventeen exact rational packings from SQUISH's third request

    upper bound confirmed

    Chaoweeraprasit after Couzo, Xu, Goebel, Schadt, Ellsworth, Hajba, Levy · SQUISH third request 2026-10-09 · packet · register

  21. 2026-10-09 published T-138 · cases 131, 270, 302, 303

    Exact witnesses at Mishapolk's printed ceilings, the smallest known at 103 and 258 when registered

    upper bound confirmed

    Mishapolk after Stenlund, Friedman, Ellsworth, Chaoweeraprasit, Couzo, Xu, Levy · Mishapolk decimal poses 2026-10-09 · packet · register

  22. 2026-10-10 published T-140 · cases 209, 237, 270, 305

    Six more exact rational certificates from Francisco Couzo

    upper bound confirmed

    Couzo after Chaoweeraprasit, Mishapolk, Xu, Daniel, Ellsworth, Levy · Couzo certificates 2026-10-10 · packet · register

  23. 2026-10-10 published T-146 · 7 of these cases

    Exact rational certificates at fifteen counts from Evan Daniel's regularized record lists

    upper bound confirmed

    Daniel after Xu, Chaoweeraprasit, Mishapolk, Levy · Daniel regularized lists 2026-10-10 · packet · register