T-222: Daniel's smaller n154 packing, continuing Couzo's #586 arrangement, certified exactly
V3 C3 Upper bound confirmed
One complete rational source certificate reports a finite upper-bound improvement at the exact side it states: .
The certificate and its duplicate-square and outside-container controls were decided here on 20 October 2026 by both maintained exact routes, and the frozen comparison rebuilt; no route here is the source's code, so the replay is independently re-implemented. The 20 October review found no blocking defect.
Issue 694 reports a packing found by Daniel's chained explorer, which removed two squares from the register's packing (Ostashev's), and by crossovers against close relatives of Couzo's #586 packing and a later restart of his basin explorer; it asks that #586's arrangement (itself continued from Daniel's #552) and Ostashev's packing be credited as its starts, and calls it a different KKT point from #586's in the same family. Measured here pose by pose, the packing is #586's arrangement continued, three squares beyond a tenth; Ostashev's packing is not near it by pose, so his credit as the search's start rests on the source's account of the search, and Couzo's on the measured arrangement.
The author reports that his two exact checkers accept the certificate and its 10-group regularized view at the same side, and a KKT point that his second-order test leaves inconclusive, with 58 corner-corner contacts, no corner-corner MILP descent, 9 rattlers and 38 tilted squares; those are numerical evidence at 80 digits, not proofs. The source's credits say the work was done with Claude (Anthropic) under Daniel's direction.
Significance, composition and next rung
- Significance
- #586's arrangement continued to a new KKT point 1.06e-04 below the case, three squares beyond a tenth, as T-219 at 271 and T-172's 6.66e-05 at this count are; no lower bound or optimum, and the source's inconclusive second-order status bears on the minimum, not on the bound.
- Next rung
- None for the bound. V4 and C4 need a second accepted adversarial review by a distinct reviewer and a retained human oversight record; one AI review, of 20 October, is retained.
- Regularized drawings
- n = 154: a regularization of T-222’s packing by Levy (Daniel's search/regularize (MIT), evand/square-packing@675a5ea, conservative, coincide, through devtools.regularize_evand; the project’s modifications: same-side exact re-solve (devtools.regularize_same_side); at its own side; 4 free squares straightened, 5 free angles moved; identity: measured here; nearest centres one to one; 47 squares moved, at most 0.0779303; turns up to 0.851377°).
- Novelty
- previously-published Present in an identified source
The case
As published
Proven
- exact
Citation record n-154
lowerKarakuş 2026, arXiv corrects Nagamochi 2005 (confirmed T-083)
upperDaniel & Couzo, GitHub (confirmed T-222)
Open
- optimality
The case record
Results on the case
15 results in the register on , oldest first, each with what it established and how it stands now.
2005 published T-007
for
V0 C1 Lower bound incomplete on this case, superseded by T-083 and T-180 (reported)
2026-09-04 published T-085
Nagamochi 2005, Lemma 1 is false for every container with and
V3 C3 Correction confirmed
Karakuş; Vlasenko · Karakuş 2026 · chelokot Nagamochi counterexample 2026 · packet · register
2026-09-27 published T-056
Smaller packings for 49 counts from to , each certified two independent ways
V3 C3 Upper bound confirmed superseded by T-222
Couzo · franciscouzo square-packing 2026-09-27 · packet · register
2026-09-29 published T-083
for every nonsquare
V3 C3 Lower bound confirmed
Karakuş · Karakuş 2026 · source · register
2026-10-05 published T-098
Exact optima of 48 known-best packings:
s(n) ≤ S',3.5e-13to5.0e-11below each printed sideV3 C3 Upper bound confirmed on this case, superseded by T-222
Daniel after Couzo, de Winter, Ellsworth, Levy · evand exact optima 2026-10-05 · packet · register
2026-10-07 published T-113
at ten counts, to 303, from new SQUISH rational packings
V3 C3 Upper bound confirmed superseded by T-222
Chaoweeraprasit after Ellsworth · SQUISH ten packings 2026-10-07 · packet · register
2026-10-07 published T-115
at twelve counts, from the SQUISH update’s new and smaller rational packings
V3 C3 Upper bound confirmed superseded by T-222
Chaoweeraprasit after Couzo and Ellsworth · SQUISH update 2026-10-07 · packet · register
2026-10-08 published T-127
Fourteen rational refinements, seventeen complete source cases
V3 C3 Upper bound confirmed on this case, superseded by T-222
Gupta after Chaoweeraprasit, Daniel · Gupta rational refinements 2026-10-08 · packet · register
2026-10-09 published T-136
Seventeen exact rational packings from SQUISH's third request
V3 C3 Upper bound confirmed on this case, superseded by T-222
Chaoweeraprasit after Couzo, Xu, Göbel, Schadt, Ellsworth, Hajba, Levy · SQUISH third request 2026-10-09 · packet · register
2026-10-12 published T-160
A smaller packing of 154 squares from Daniel's size-chaining explorer, certified exactly
V3 C3 Upper bound confirmed superseded by T-222
Daniel after Couzo, Levy · Daniel n154 2026-10-12 · packet · register
2026-10-12 published T-172
A packing of 154 squares from Couzo, continuing Daniel's arrangement
V3 C3 Upper bound confirmed superseded by T-222
Couzo after Daniel, Ostashev, Fang, Ellsworth, Levy · Couzo issue-583 certificates 2026-10-13 · packet · register
2026-10-13 published T-180
Closed-form lower bound for every non-square , reported
V0 C1 Lower bound reviewed
Hosono · wand125 closed form 2026-10-14 · packet · packet · register
2026-10-13 published T-182
Exact rational certificates at 154, 211 and 241 from Couzo
V3 C3 Upper bound confirmed on this case, superseded by T-222
Couzo after Daniel, Ostashev, BuddenPing, Fang, Ellsworth, Levy · Couzo certificates 2026-10-13 · packet · register
2026-10-14 published T-186
Exact certificates at twelve counts from Polkovskyi, tightening the smallest reported there
V3 C3 Upper bound confirmed on this case, superseded by T-222
Polkovskyi after Ostashev, Couzo, PingYou Ltd, Levy · Mishapolk KKT refinements 2026-10-14 · packet · register
2026-10-20 published T-222 this result
Daniel's smaller n154 packing, continuing Couzo's #586 arrangement, certified exactly
V3 C3 Upper bound confirmed
Daniel after Couzo, Ostashev, Levy · Daniel n154 sweep 2026-10-20 · packet · packet · register
Links
- On this site
- Case record, · Frontier row, · T-222 in the results table
On GitHub, at main
- Register
- T-222 in
results.yaml, line 30367 - Evidence
E-evand-694-n154-report·E-evand-694-n154-exact-feasibility- Proofs and certificates
- certificate
candidates - Sources
- Daniel n154 sweep 2026-10-20 (its own site, retained copy)
- Source packet
resources/web/evand-n154-sweep-2026-10-20/README.md·resources/web/evand-n308-2026-10-19/README.md- Artifacts
10 artifacts and controls
resources/web/evand-n154-sweep-2026-10-20/README.mdresources/web/evand-n154-sweep-2026-10-20/acquisition/claims.jsonresources/web/evand-n154-sweep-2026-10-20/source/search/packer/candidates/s154_sw.certresources/web/evand-n154-sweep-2026-10-20/receipts/exact-certification.json.xzdevtools/upper_bound_reports.pydocs/project/reviews/review-2026-10-20-upper-bound-imports-689-694.mdresources/web/evand-n308-2026-10-19/review/review-2026-10-20/README.mdtests/test_upper_bound_reports.pytests/test_upper_bound_reports_689_694.pyresources/web/evand-n154-sweep-2026-10-20/receipts/exact-certification.json.xz- Case file
frontier/n-154.md(verified lower, verified upper, reported lower, reported upper)