A specialized O(N)-memory engine (b33b_scan.c) computes ·b33b's Sprague-Grundy sequence EXACTLY to N=300,000,000, 1200× further than round 1, by reducing each step (n>M+6) to a single exact 3-split reachability test for the lone unrealized terminal value M. It reproduces ALL 250,001 round-1 nim-values (from the independent Θ(N²) pair-XOR-bitset engine hexfast.c) with 0 differences; an independent V2-engine run to 500,000 agrees on all 500,001 values including the newly detected exceptions at 390114, 390116, 390118; and a built-in full-mex self-audit reports audit_fail=0 at every checkpoint.
Evidence
Provenance
Reviews
Engine exactness independently confirmed: b33b_scan.c compiled fresh + matched an independent Theta(N^2) engine on all 250,001 values, 0 diffs (genuinely different algorithms). 500k V2 incl. new exceptions not re-run, but 250k+10M agreement makes it credible.
Referee-commissioned independent blind review (Fable-5). Two independent SG engines agree with 0 diffs on all 250,001 values (a real cross-check, not self-consistency); cascade law verified to N=1e7 live + the full 59-member table re-derived. Confidence labels are honest -- the non-periodicity conclusion is explicitly a conjecture/speculation; the large-N computation is NOT over-read as a proven asymptotic law. Fable lean: GREEN. Only the raw 3e8 mega-run itself wasn't personally awaited (its derived byproducts all check out). Final referee CALL pending.