Consecutive Cycle Sums

Abstract

Consider placing the numbers $1,\dots ,n$ consecutively around an $n$-cycle. We ask for a given $n$, which numbers $k$ can be written as a sum of consecutive numbers on the $n$-cycle. If all numbers between $1$ and $T_n$, the $n$th triangular number, can be written as a sum this way we say the $n$-cycle is complete. Our main result shows that for $n\ge 8$, $n$-cycles are incomplete.

7 pages, 2 figures