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A002823 Number of period-n solutions to a certain "universal" equation related to transformations on the unit interval.
(Formerly M2357 N0933)
1, 1, 3, 4, 9, 14, 27, 48, 93, 163, 315, 576, 1085 (list; graph; refs; listen; history; text; internal format)



a(n) <= A000048(n), since the solutions counted here are a subset of the solutions counted by A000048 (called U sequence in the paper). The observed equality for prime n means that there are in this case no harmonics, which would disappear. - M. F. Hasler, Nov 05 2014


N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


Table of n, a(n) for n=3..15.

N. Metropolis, M. L. Stein and P. R. Stein, On finite limit sets for transformations on the unit interval, J. Combin. Theory, A 15 (1973), 25-44; reprinted in P. Cvitanovic, ed., Universality in Chaos, Hilger, Bristol, 1986, pp. 187-206.

P. R. Stein, Letter to N. J. A. Sloane, Jun 02 1971


Cf. A000048, A001372.

Sequence in context: A263821 A007293 A014596 * A109509 A006053 A051841

Adjacent sequences: A002820 A002821 A002822 * A002824 A002825 A002826




N. J. A. Sloane



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Last modified December 7 19:19 EST 2022. Contains 358669 sequences. (Running on oeis4.)