English

Limit points of Nathanson's Lambda sequences

Number Theory 2019-02-26 v1

Abstract

We consider the set An=j=0{εj(n)nj ⁣:εj(n){0,±1,±2,...,±n/2}}A_{n}=\displaystyle\cup_{j=0}^{\infty}\{\varepsilon_{j}(n)\cdot n^j\colon\varepsilon_{j}(n)\in\{0,\pm1,\pm2,...,\pm\lfloor{{n}/{2}}\rfloor\}\} . Let SA=aAAa\mathcal{S}_{\mathcal{A}}= \bigcup_{a \in\mathcal{A} } A_{a} where AN\mathcal{A}\subseteq \mathbb{N}. We denote by λA(h)\lambda_{\mathcal{A}}(h) the smallest positive integer that can be represented as a sum of hh, and no less than hh, elements in SA\mathcal{S}_{\mathcal{A}}. Nathanson studied the properties of the λA(h)\lambda_\mathcal{A}(h)-sequence and posed the problem of finding the values of λA(h)\lambda_\mathcal{A}(h). When A={2,i}\mathcal{A}=\{2,i\}, we represent λA(h)\lambda_{\mathcal{A}}(h) by λ2,i(h)\lambda_{2,i}(h). Only the values λ2,3(1)=1\lambda_{2,3}(1)=1, λ2,3(3)=5\lambda_{2,3}(3)=5, λ2,3(3)=21\lambda_{2,3}(3)=21 and λ2,3(4)=150\lambda_{2,3}(4)=150 are known. In this paper, we extend this result. For any odd i>1i>1 and h{1,2,3}h\in\{1,2,3\}, we find the values of λ2,i(h)\lambda_{2,i}(h). Furthermore, for fixed h{1,2,3}h\in\{1,2,3\}, we find the values of λ2,i(h)\lambda_{2,i}(h) that occur infinitely many times as ii runs over the odd integers bigger than 1. We call these numbers the limit points of Nathanson’s lambda sequences\textit{limit points of Nathanson's lambda sequences}.

Keywords

Cite

@article{arxiv.1902.08814,
  title  = {Limit points of Nathanson's Lambda sequences},
  author = {Satyanand Singh},
  journal= {arXiv preprint arXiv:1902.08814},
  year   = {2019}
}

Comments

10 pages, 2 tables

R2 v1 2026-06-23T07:48:55.581Z