trureturingGitHub MATHEMATICAL ATLAS

RESEARCH / Focused target

The integer source and dyadic parity of A397592

Literature status: not recheckedRepository record: proved

RELEASED FOUNDATIONS / PROPOSED CONNECTION

Research connections

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Problem

The question

Paul D. Hanna's OEIS A397592 (July 10, 2026), revision 18, has NAME:

G.f. A(x) such that the sum of the first n coefficients in A(x/n)^n equals 2^(n-1) for n >= 1.

Its sole conjecture is:

Conjecture: for n > 3, a(n) is odd iff n is of the form 2^k-1 or 2^k+1 (k > 1).

The FORMULA states A(x)=Sum_{n>=0} a(n)*x^n; the original offset is 0 and a(0)=1. For A in Z[[X]], A_Q is its coefficientwise image in Q[[X]], namely A.map (Int.castRingHom Rat). The exact source and single result are:

def SourceA397592 (A : PowerSeries Int) : Prop :=
  PowerSeries.constantCoeff A = 1 ∧
    ∀ m : Nat, 0 < m →
      (Finset.range m).sum (fun j => PowerSeries.coeff j
        ((PowerSeries.rescale ((m : Rat)⁻¹)
          (A.map (Int.castRingHom Rat))) ^ m)) = (2 : Rat) ^ (m - 1)

theorem result :
  (∃! A : PowerSeries Int, SourceA397592 A) ∧
  (∀ A : PowerSeries Int, SourceA397592 A → ∀ n : Nat, 3 < n →
    (Odd (PowerSeries.coeff n A) ↔
      ∃ k : Nat, 1 < k ∧ (n = 2 ^ k - 1 ∨ n = 2 ^ k + 1)))

These are ordinary formal powers, not compositional iterates; there is no convergence or factorial normalization. The sum includes j=0,...,m-1 for every natural m>0. The separate integer-existence-and-uniqueness conjunct excludes an unproved integrality premise.

Motivation

Our foothold

This first-tier 2026 external named conjecture is the question_answered in #8006, created 2026-09-15T03:15:36Z before probes. A397591 supplies the distinct y=0 endpoint; A397592 is the y=2 source. The same parity pattern does not identify their series.

Gap

Missing bridges

The A397591 series F has constant term zero, offset 1, and satisfies X^(m-1)^m/(1-mX)=0 for m>1. Its endpoint does not by itself establish integer existence for A397592 or an all-degree parity comparison. A397590 attests A(X,0)=1-F(X) and A397592(n)=Sum_{k=0..n} 2^k T(n,k). These source identities do not supply a proof of general triangle integrality.

Route

Proposed approach

Multiply the rational NAME sum in row m=n+1 by m^n. The coefficient rescaling law and the geometric-series convolution give the integer row R_n=[X^n]A^(n+1)/(1-(n+1)X)=(2(n+1))^n. Both directions hold for every m>0, including m=1. The existing exact normalization gives R_n=(n+1)N_n for n>0. Cancellation takes place in the integers and gives N_n=2^n(n+1)^(n-1).

Let t_n=2^n(n+1)^(n-1) for n>0 and give the forcing series constant term zero. Add this forcing series to the existing coefficient-correction map advance. Its agreement property increases the number of stable coefficients by one. Iterating from 1 therefore stabilizes coefficientwise to an integer series A fixed by the forced map. The fixed-point equation gives N_n=t_n, and the complete source equivalence gives SourceA397592(A). Strong induction using normalized_change proves uniqueness among integer source solutions.

Only then map to ZMod 2. For positive n the forcing term maps to zero, so normalized_unique identifies every satisfying source modulo two with the existing homogeneous solution. The latter equals 1 minus the A397591 series. Above degree three their coefficients agree modulo two, and hanna_conjecture gives exactly the two dyadic alternatives.

The new iteration, stabilization, source equivalences and parity adapters are local to the sole theorem. A397594/y=4, arbitrary even parameters, full triangle integrality, positivity and asymptotics are outside its claim.

Falsifier

What would falsify this route

An integer source and an n>3 violating either direction of the parity iff would refute the parity assertion. Failure of integer existence, or two distinct integer sources, would refute the well-posedness conjunct. A finite prefix, a conditional integer-source assumption, a shifted index or a missing strict bound changes the target instead of resolving it.

Evidence

Evidence to collect

The module D5/S1/Recurrence/LinearRows/DoubledLinearExponentDyadicSupport contains the source predicate SourceA397592 and the single theorem result. Its source citation is D5/L/hanna2026a397592.

The existing LinearExponentDyadicSupport endpoint has stored identities:

  • hanna_conjecture: sha256:257441c32f0b491832283533f85a4a8f2894bd3bb24da35790b5c8539a682503.
  • generatingSeries: sha256:5edab5bd8bbb3730bb76f331bab1d2a071ce873a70eecd471722169450fdcefe.

Those identities locate the y=0 endpoint, not an A397592 proof. The numerical appendix of Library/Words/oeis2026triage0911b.md records an N=100 integer recurrence experiment and zero parity counterexamples at n=4,...,100. Its program and data are finite research evidence, not evidence for all indices.

Triage

Scope assessment

The admission route is open-problem-resolution under CLAUDE 3.2 for the exact external conjecture registered in #8006. The theorem has proof_shape: content: the forced integer construction and stabilization supply a new unbounded existence argument. The source predicate is a necessary definition. escape_witness: none uses the external named-problem admission basis; computational_content.kind: none applies to both declarations. The public mathematical surface consists of the necessary source predicate and one result; adapting facts belong inside its proof. The stated problem is unbounded and symbolic. It includes neither A397594 nor a full A397590 triangle result.

ASSUMED-UNVERIFIED

Unverified assumptions

The source snapshot in #8006 is revision 18, Jul 11 2026 03:34:44. The live text request returned HTTP200 (4,200 bytes); the complete mirror entry is 3,990 bytes, SHA-256 ec2009bc22f7209c0403adc0c2909bffbc24016ef40c9eb8b0c131585c8e51d8. The Library note fixes the source locators; later source changes are outside that snapshot.

Bounded exact A397592 searches recorded Crossref HTTP200/0, OpenAlex HTTP200/0, MathOverflow HTTP200/empty with no further page, and a public GitHub Lean-code index count of 0. D5 and pinned Mathlib db584cd6d46c92f209a44c0f1c829460d327499d supplied the y=0 endpoint and generic series APIs, with no exact resolution in the inspected scope: dominating_theorem_search: not-found-in-searched-scope.

Only 20 of 34 broad OpenAlex records and nine MathOverflow titles were screened; not all answers were read, and broad Crossref ranking is not an absence result. Fried's arXiv:2607.24832 and Heninger–Rains–Sloane were only partially read; no verified reduction from the latter's fixed-n root integrality to this varying-row source is supplied. arXiv query HTTP429 and timeouts, Google's JavaScript shell, unread papers or portions, b-files and other unopened material give no negative evidence. Differently named, differently indexed, unindexed or new proofs remain unexcluded. Neither global priority nor exhaustive absence of prior proofs is claimed.

Dossier & anchor history

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