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Published online by Cambridge University Press:  22 November 2019

School of Mathematical and Physical Sciences,University of Newcastle, Newcastle, NSW 2308, Australia email
School of Mathematics and Statistics,University of New South Wales, Sydney, NSW 2052, Australia email


A Ducci sequence is a sequence of integer $n$-tuples obtained by iterating the map

$$\begin{eqnarray}D:(a_{1},a_{2},\ldots ,a_{n})\mapsto (|a_{1}-a_{2}|,|a_{2}-a_{3}|,\ldots ,|a_{n}-a_{1}|).\end{eqnarray}$$
Such a sequence is eventually periodic and we denote by $P(n)$ the maximal period of such sequences for given odd $n$. We prove a lower bound for $P(n)$ by counting certain partitions. We then estimate the size of these partitions via the multiplicative order of two modulo $n$.

Research Article
© 2019 Australian Mathematical Publishing Association Inc.

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The second author was supported in part by the Australian Research Council Grant DP180100201.


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