English

On the Frobenius number of certain numerical semigroups

Number Theory 2022-03-02 v4

Abstract

Let 0<λ10<\lambda\leq1, λ{24,27,210,213,}\lambda\notin\left\{\frac24, \frac27, \frac2{10}, \frac2{13}, \ldots\right\}, be a real and pp a prime number, with [p,p+λp][p,p+\lambda p] containing at least two primes. Denote by fλ(p)f_\lambda(p) the largest integer which cannot be written as a sum of primes from [p,p+λp][p,p+\lambda p]. Then fλ(p)2+2λp, as p goes to infinity.f_\lambda(p)\sim\left\lfloor2+\frac2\lambda\right\rfloor\cdot p\text{, as }p\text{ goes to infinity.} Further a question of Wilf about the 'Money-Changing Problem' has a positive answer for all semigroups of multiplicity pp containing the primes from [p,2p][p,2p]. In particular, this holds for the semigroup generated by all primes not less than pp. The latter special case was already shown in a previous paper.

Keywords

Cite

@article{arxiv.2001.11204,
  title  = {On the Frobenius number of certain numerical semigroups},
  author = {Michael Hellus and Anton Rechenauer and Rolf Waldi},
  journal= {arXiv preprint arXiv:2001.11204},
  year   = {2022}
}

Comments

15 pages, 2 figures