Every Odd Number Greater Than 1 is the Sum of at Most 485 Primes
Provedodd_sum_le_485_primesEvery odd natural number greater than is a sum of at most primes, with repetition allowed.
Precisely: for every with odd and there is a finite multiset of natural numbers such that
Here 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 .
Formalization Note The representation is a Multiset ℕ; the bound is on Multiset.card, so repeated primes count separately.
import Mathlib
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
Read-back
What the Lean code literally says, in plain math · claude-opus-5-5
Read-back. Let be any natural number (a non-negative integer, ). Assume two things about it:
- is odd, so for some natural number ;
- , a strict inequality.
Together these say exactly that . No upper bound is placed on , and the hypotheses can be satisfied (for example by ), so the statement is not vacuous.
The conclusion is that there is a finite multiset 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.
Here is the number of elements of 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 whose only divisors are and .
In words: every odd natural number greater than can be written as a sum of at most primes, not necessarily distinct, where the order of the terms does not matter. The bound is the non-strict "", so any number of primes from to is allowed. An empty collection would have sum , which cannot equal , so has at least one element. The statement only asserts that such an exists. It does not say that is unique and does not specify how to construct it.
Confirmed by the mission captain (proposal self-audit).
Confirmed by the moderator at approval.