Integers that are not the sum of positive powers
Brennan Benfield, Oliver Lippard
TL;DR
This work advances the generalized Waring problem by combining computational sieving with partition-theoretic methods to characterize the sets of integers not expressible as sums of $j$ positive $k$-th powers. It unifies Zenkin’s framework with new $n^*$-based criteria to propagate representations to larger numbers and computes the obstruction sets $\mathbf{B}^k_j$ for $3\le j\le9$ across several $k$, proving Zenkin’s conjecture $g(1,k)=57$ and deriving both unconditional and conjectural bounds for $G(1,k)$. The paper presents detailed proofs for key cases (notably $k=5$–$9$) and develops general properties of $\mathbf{B}$-sets, including chain-inclusion and stabilization phenomena, supported by extensive computational data. The results refine our understanding of when every sufficiently large integer is representable as a sum of $j$ $k$-th powers and illuminate the structure and growth of nonrepresentable sets, with implications for future bounds in Waring-type problems. The methods blend algorithmic number theory with analytic and combinatorial tools to push the boundaries of known $G(1,k)$ and $g(1,k)$ values.
Abstract
The generalized Waring problem asks exactly which positive integers cannot be expressed as the sum of $j$ positive $k$-th powers? Using computational techniques, this paper refines an approach introduced by Zenkin, establishes results for the individual cases $5 \le k \le 9$, and resolves conjectures of Zenkin and the OEIS. This paper further establishes theoretical results regarding the properties of the sets of integers that are not the sum of $j$ positive $k$-th powers. The notion of Waring's problem is further extended to the finite sets of non-representable numbers where $G(1,k) < j < g(1,k)$. Improved computational techniques and results from Waring's problem are used throughout to catalog the sets of such integers, which are then considered in a general setting.
