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Every Odd Number Greater Than 1 is the Sum of at Most 485 Primes

Proved
odd_sum_le_485_primes

by xuanji · Oct 3, 2026 · Mathlib 0df444a (Lean v4.33.1)

goldbachnumber-theoryschnirelmann-densitysieve-theory

Every odd natural number greater than 111 is a sum of at most 485485485 primes, with repetition allowed.

Precisely: for every n∈Nn \in \mathbb{N}n∈N with nnn odd and n>1n > 1n>1 there is a finite multiset sss of natural numbers such that

∣s∣≤485,every p∈s is prime,∑p∈sp=n.|s| \le 485, \qquad \text{every } p \in s \text{ is prime}, \qquad \sum_{p \in s} p = n.∣s∣≤485,every p∈s is prime,p∈s∑​p=n.

Here ∣s∣|s|∣s∣ counts elements with multiplicity, so the same prime may be used several times, and the order of the summands is irrelevant.

This is the campaign statement of Odd numbers as sums of primes with the value 485485485.

Formalization Note The representation is a Multiset ℕ; the bound is on Multiset.card, so repeated primes count separately.

Preamble
import Mathlib
Formal statement
theorem odd_sum_le_485_primes (n : ℕ) (hodd : Odd n) (hn : 1 < n) :
    ∃ s : Multiset ℕ, s.card ≤ 485 ∧ (∀ p ∈ s, Nat.Prime p) ∧ s.sum = n := by
  sorry
Source
AI-assisted explicit calculation (unpublished, October 2026), improving the K = 100001 note: weighted eighth-moment / Hölder argument, sigma(A) >= 1/175, m = 121, K = 4m + 1 = 485; framework: P. Pollack, Not Always Buried Deep, Ch. 6 §6, pp. 196–201, https://www.pollack-math.net/NABDofficial.pdf
Read-back

What the Lean code literally says, in plain math · claude-opus-5-5

Read-back. Let nnn be any natural number (a non-negative integer, n∈{0,1,2,… }n \in \{0, 1, 2, \dots\}n∈{0,1,2,…}). Assume two things about it:

  • nnn is odd, so n=2k+1n = 2k + 1n=2k+1 for some natural number kkk;
  • 1<n1 < n1<n, a strict inequality.

Together these say exactly that n∈{3,5,7,9,… }n \in \{3, 5, 7, 9, \dots\}n∈{3,5,7,9,…}. No upper bound is placed on nnn, and the hypotheses can be satisfied (for example by n=3n = 3n=3), so the statement is not vacuous.

The conclusion is that there is a finite multiset SSS of natural numbers with all three of the following properties. A multiset is an unordered collection in which an element may appear more than once.

∣S∣≤485,every p∈S is prime,∑p∈Sp=n.|S| \le 485, \qquad \text{every } p \in S \text{ is prime}, \qquad \sum_{p \in S} p = n .∣S∣≤485,every p∈S is prime,p∈S∑​p=n.

Here ∣S∣|S|∣S∣ is the number of elements of SSS counted with multiplicity, so a prime that appears several times is counted that many times. The sum also counts each element with its multiplicity. "Prime" has its usual meaning: a natural number p≥2p \ge 2p≥2 whose only divisors are 111 and ppp.

In words: every odd natural number greater than 111 can be written as a sum of at most 485485485 primes, not necessarily distinct, where the order of the terms does not matter. The bound is the non-strict "≤485\le 485≤485", so any number of primes from 111 to 485485485 is allowed. An empty collection would have sum 000, which cannot equal nnn, so SSS has at least one element. The statement only asserts that such an SSS exists. It does not say that SSS is unique and does not specify how to construct it.

Human review
  • Endorsed by Shuze Chen · Oct 4, 2026

    Confirmed by the moderator at approval.

  • Endorsed by xuanji · Oct 4, 2026

    Confirmed by the mission captain (proposal self-audit).

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