n = 30 open ★=

117672000≤s(30)≤6

The best packing known for 30 squares, side 6,
5.8836
567
5.4776.477
nn+1

Proven

5.883500≤s(30)≤6

  • new result
  • exact

Citation record n-030

lowerwand125 after Tokoharu, Levy et al. 2026, GitHub (confirmed T-109)

Open

  • optimality

Bounds

Best known packing

6

Construction
grid
Tilt angles
0∘
Source
[Kingbird]
Evidence
E-kingbird-upper-register
Verified upper bound

6

The reported value, verified here.

Evidence
E-basic-grid-upper
Reported lower bound

117672000

Proved by
wand125 2026
Kind
counting
Scope
Unrestricted unit-square packing with independent rotations and disjoint interiors.
Note
wand125's square-packing-bounds (6 October 2026) reports s(30)≥11767/2000 from a density of 402 uniform rectangles of total mass 2999999/100000, on a net the certificate declares: core side 1999/2000 and 832 half-angle tangents of step 1/2006, accepted there at every direction by sqverify-proof-net, the source's copy of this repository's sqverify_fast changed to read a declared net (a check2 bundle, with no C++ record). It is above the 47/8 the record reported (T-068). sqverify-fast, this repository's clean-room measure verifier, decided it here at all 832 directions on 6 October 2026.
Source
[wand125 mixed bounds check2 2026-10-06]
Evidence
E-n030-wand125-mixed-58835-report
Verified lower bound

117672000

The reported value, verified here.

Evidence
E-n030-wand125-mixed-58835-sqverify-fast-replay
Gap

2332000= 0.1165

Verified upper minus verified lower.

Results in the register

Verification

upper: replayed here; lower: replayed here

—

Rigidity

not rigid, numerically checked, numerical multiprecision

Evidence: E-translation-escape-not-rigid

Scope

Square 24 of the retained witness (witness id 25) translates 1 along (0, 1) with the packing still valid, so the configuration admits a non-trivial feasible motion; 6 of its 30 squares do. Every constraint is exactly affine in the slide parameter, so the arithmetic carries no linearization error, but the coordinates are the witness's own finite-precision transcription: this settles the retained configuration, not the true optimum. Rigidity and optimality are independent, and this bears only on the former.

s(30) — open

External intake, 2026-10-06. wand125’s check2 source reports s(30)≥11767/2000=5.8835 (T-109), from a density of 402 rectangles of total mass 2999999/100000<30, on a net the certificate declares: core side 1999/2000 and 832 half-angle tangents of step 1/2006. Since 1999/2000·(1+1/2006)<1, every unit square contains a core at a net angle strictly in its interior. The source ships no record of its C++ checker for it: it accepts it at every direction with its copy of this repository’s sqverify_fast, changed to read a declared net. It is above the reported 47/8 (T-068) by 0.0085. This repository’s clean-room verifier sqverify-fast decided it here on 6 October 2026 at all 832 directions of its net, and refused two mutants scaled below coverage one: confirmed, re-implemented sharing the producer’s components (the source’s check is a copy of the same crate), so it is also the verified lower bound. wand125’s README says parts of the work were produced with AI assistance under human direction.

External intake, 2026-10-01. wand125’s rectangle-density source reports s(30)≥47/8=5.875, since superseded (T-109), with total mass 2999/100=29.99<30, accepted by Tokoharu’s unchanged interval checker. The complete 201-direction coverage replay here accepted it again, after this repository’s exact audit checked that the regenerated checker input is the published one and checked the mass and net premises, so it was also verified until 2026-10-06, when the certificate above superseded it in both lanes. wand125’s README says parts of the work were produced with AI assistance under human direction.

External intake, 2026-09-27. wand125’s rectangle-density source reports a direct 1173/200=5.865 certificate for this case, whose reported bound the 2026-10-01 intake above raises, with total mass 2999/100=29.99<30, accepted by Tokoharu’s unchanged interval checker. This repository’s exact audit checks that the regenerated checker input is the published one, and checks the mass and net premises; the complete coverage replay has not yet run here, so the verified lower bound is unchanged. wand125’s README says parts of the work were produced with AI assistance under human direction.

External intake, 2026-09-22. Tokoharu’s retained rectangle-density source reports s(29)≥571/100=5.71; monotonicity carries the reported bound to n=30. The complete source replay verifies the source premise, so the same monotonicity argument verifies the bound at n=30. Tokoharu’s README says parts of the work were produced with AI assistance under human direction.

Open. The verified interval is 11767/2000=5.8835≤s(30)≤6, with width 0.1165. Its lower end is wand125’s check2 certificate on a declared net (T-109, 2026-10-06, V3/C3), which superseded its rectangle-density certificate of 1 October at 47/8=5.875 (T-074, replayed here on 2026-10-02), that one its replayed 1173/200 (T-045, 2026-10-02), and that one Tokoharu’s 571/100 carried from n=29.

The packing

The record catalogue does not picture n=30: no arrangement has ever been found that beats the trivial ⌈30⌉=6 grid, so the grid is still the best known packing. That is a statement about what has been searched, not a proof.

The lower bound

The verified lower bound is 11767/2000=5.8835, from wand125’s check2 certificate of 6 October on a declared net (T-109), decided here by sqverify-fast at every direction of its net. Before it, 47/8=5.875, from its own n30 rectangle-density certificate of 1 October, replayed in full here (T-074); its certificate of 27 September, 1173/200=5.865 (T-045), held the field earlier on 2 October. Until then it was 571/100: the complete n29 interval replay verifies that bound, and deleting one square from any hypothetical packing proves it for n30 too. A method-distinct rectangle coverage implementation would add confidence and improve generalization, but it is not a missing premise of either bound.

Corrected 2 October 2026: Nagamochi’s Lemma 1 is false (Karakuş 2026), so his closed form below is now a reported bound whose published proof is incomplete (review). This register had recorded that proof as verified, its own error, logged as defect D-516. Nagamochi’s earlier general closed form remains part of the evidence history and applies to every N≥4:

s(N)≥min{⌈N⌉,N−2⌊N⌋+1+1}

Verification Code

The programs behind this case’s verified bounds, by their evidence. The code column says how the code that ran stands to the code its producer used. VERIFIERS.md says what each program is and whose it is.

bound evidence run code programs
verified lower E-n030-wand125-mixed-58835-sqverify-fast-replay replayed here shared components V-sqverify-fast (first-party)
verified upper E-basic-grid-upper replayed here independent V-check-basic-bounds (first-party)