English

An Extreme Family of Generalized Frobenius Numbers

Number Theory 2013-10-07 v2 Combinatorics

Abstract

We study a generalization of the \emph{Frobenius problem}: given kk positive relatively prime integers, what is the largest integer g0g_0 that cannot be represented as a nonnegative integral linear combination of these parameters? More generally, what is the largest integer gsg_s that has exactly ss such representations? We illustrate a family of parameters, based on a recent paper by Tripathi, whose generalized Frobenius numbers g0, g1, g2,...g_0, \ g_1, \ g_2, ... exhibit unnatural jumps; namely, g0, g1, gk, g(k+1k1), g(k+2k1),...g_0, \ g_1, \ g_k, \ g_{\binom{k+1}{k-1}}, \ g_{\binom{k+2}{k-1}}, ... form an arithmetic progression, and any integer larger than g(k+jk1)g_{\binom{k+j}{k-1}} has at least (k+j+1k)\binom{k+j+1}{k-} representations. Along the way, we introduce a variation of a generalized Frobenius number and prove some basic results about it.

Keywords

Cite

@article{arxiv.1005.2692,
  title  = {An Extreme Family of Generalized Frobenius Numbers},
  author = {Matthias Beck and Curtis Kifer},
  journal= {arXiv preprint arXiv:1005.2692},
  year   = {2013}
}

Comments

5 pages, to appear in Integers: the Electronic Journal of Combinatorial Number Theory