Counting partitions into small blocks with power-of-three sums

Can {1,…,n} always be partitioned into nonempty blocks of at most three distinct integers, each summing to a power of three? Beyond existence, which n have exactly one, exactly two or at least three such partitions?

Why it matters and what counts as progress

Why it matters: The counting question distinguishes unique or rare decompositions from the broader existence theorem.

What counts as progress: A proof of existence for every n, followed by an exhaustive count classification; an exception to a proposed one- or two-partition family also changes the classification.

How the problem developed

  1. 31 Jul 2025 · Conjecture and partial results [1]

    Vladimir Gurvich and Mariya Naumova Conjectured that every initial interval of positive integers has a partition into parts of size at most three with power-of-three sums; constrained possible minimal counterexamples and verified cases computationally through 844.

  2. 18 Oct 2026 · Reported theorem and formalization [2]

    Deep Bhattacharjee and Ushashi Bhattacharya Reported an explicit recursive partition for every n and provided a Lean 4 formalization; this proves the m=3 existence conjecture and the stated m=2-or-3 classification.

AI contributions 2

AI-centered Lean proof classifies base-three partition counts

For partitions of {1,…,n} into nonempty blocks of at most three elements whose sums are powers of three, the count is exactly one on N_u={1,2,3,4}∪{3ᵗ+d:t≥2, d∈{−4,−2,−1,0,1,2,3,5}}; exactly two on E₂={13}∪{3ᵗ−3:t≥2}∪{3ᵗ−6:t≥3}; and at least three otherwise.

Reported

Sources

  1. Gurvich and Naumova, Partitioning [n] into subsets of size at most m such that all sums are powers of m
  2. Bhattacharjee and Bhattacharya, Partitioning [n] into parts of size at most three whose sums are powers of three (paper and Lean formalization)
  3. Jones, base-three partition classification
  4. AI and human contributions to the partition proof
  5. Lean verification of partition counts
  6. Gurvich and Naumova, base-three partition paper
  7. Jones’s partition formalization
  8. Partition proof attribution
  9. Partition proof verification record
  10. Gurvich and Naumova’s conjecture and partial results
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