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A087888 Given a sequence u consisting just of 1's and 2's, let f(u)(n) be the length of n-th run. Then we may define a sequence u = {a(n)} by a(n)=f^(n-1)(u)(1) (starting with n=1). 2
2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 2, 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, 2, 1, 1, 2, 1, 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

There are exactly three infinite sequences satisfying this relation, namely this sequence, A087889 and A087890.

LINKS

Table of n, a(n) for n=1..105.

CROSSREFS

Cf. A000002, A087889, A087890.

Sequence in context: A081592 A255934 A085028 * A296299 A109494 A074292

Adjacent sequences:  A087885 A087886 A087887 * A087889 A087890 A087891

KEYWORD

easy,eigen,nonn

AUTHOR

Vincent Nesme (vincent.nesme(AT)ens-lyon.fr), Oct 13 2003

EXTENSIONS

The description was not quite clear to me but I hope I have edited it correctly. - N. J. A. Sloane.

STATUS

approved

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Last modified January 15 19:06 EST 2019. Contains 319171 sequences. (Running on oeis4.)