Iteration Sequence

A sequence {a_j} of positive integers is called an iteration sequence if there exists a strictly increasing sequence {s_k} of positive integers such that a_1=s_1>=2 and a_j=s_(a_(j-1)) for j=2, 3, .... A necessary and sufficient condition for {a_j} to be an iteration sequence is


for all j>=3.

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Kimberling, C. "Interspersions and Dispersions." Proc. Amer. Math. Soc. 117, 313-321, 1993.

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Iteration Sequence

Cite this as:

Weisstein, Eric W. "Iteration Sequence." From MathWorld--A Wolfram Web Resource.

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