The Hofstadter consecutive-sum sequence omits infinitely many positive integers

Fuente: arXiv
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Main Author: Tang, Quanyu
Format: Preprint
Published: 2026
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author Tang, Quanyu
author_facet Tang, Quanyu
contents Let $(a_n)_{n\ge 1}$ be the greedy self-generating sequence defined by $a_1=1$, $a_2=2$, and, for $k\ge 3$, by taking $a_k$ to be the least integer greater than $a_{k-1}$ that can be written as a sum of at least two consecutive earlier terms. Hofstadter asked about the asymptotic behavior of this sequence. In this paper we prove that $$ n+Ω(\log\log n)\le a_n \ll n^{4175/2506+o(1)}. $$ In particular, $(a_n)_{n\ge1}$ omits infinitely many positive integers, thereby settling a conjecture from the OEIS entry A005243.
format Preprint
id arxiv_https___arxiv_org_abs_2603_09939
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The Hofstadter consecutive-sum sequence omits infinitely many positive integers
Tang, Quanyu
Number Theory
Combinatorics
Primary 11B83, Secondary 11D61
Let $(a_n)_{n\ge 1}$ be the greedy self-generating sequence defined by $a_1=1$, $a_2=2$, and, for $k\ge 3$, by taking $a_k$ to be the least integer greater than $a_{k-1}$ that can be written as a sum of at least two consecutive earlier terms. Hofstadter asked about the asymptotic behavior of this sequence. In this paper we prove that $$ n+Ω(\log\log n)\le a_n \ll n^{4175/2506+o(1)}. $$ In particular, $(a_n)_{n\ge1}$ omits infinitely many positive integers, thereby settling a conjecture from the OEIS entry A005243.
title The Hofstadter consecutive-sum sequence omits infinitely many positive integers
topic Number Theory
Combinatorics
Primary 11B83, Secondary 11D61
url https://arxiv.org/abs/2603.09939