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A025143 Unique sequence a such that a(1) = 2 and r(r(a)) = a != r(a), where for any sequence s of 1's and 2's, r(s(n) := length of n-th run of same symbols in s; r(a) is sequence A025142. 12
2, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 1, 2, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Probably A288724 is the same sequence. - R. J. Mathar, Sep 02 2017

REFERENCES

C. Kimberling, Problem 90: Run-length sequences, Mathematische Semesterberichte, 44 (1997) 94-95.

LINKS

Table of n, a(n) for n=1..111.

CROSSREFS

Differs from A014675 in many entries starting at entry 8.

Cf. A288724.

Sequence in context: A123018 A100429 A049710 * A174314 A237253 A080634

Adjacent sequences:  A025140 A025141 A025142 * A025144 A025145 A025146

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified August 8 06:27 EDT 2020. Contains 336290 sequences. (Running on oeis4.)