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A157129 a(n)=(length of n-th run divided by 2) using 1 and 2 and starting with 1,1. 2
1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

FORMULA

As for the Kolakoski sequence we suspect sum(k=1,n,a(k))=(3/2)*n+o(n)

EXAMPLE

Third run = 1,1,1,1 of length 4 thus a(3)=4/2=2.

PROG

(PARI) ?w=[1, 1]; for(n=2, 1000, for(i=1, w[n], w=concat(w, 1+(n+1)%2)); w; ) ?a(n)=w[n]

CROSSREFS

Cf. A000002

Sequence in context: A308884 A101598 A342461 * A101615 A246359 A328114

Adjacent sequences:  A157126 A157127 A157128 * A157130 A157131 A157132

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Feb 23 2009

STATUS

approved

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Last modified April 14 10:14 EDT 2021. Contains 342949 sequences. (Running on oeis4.)