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Revision History for A096365 (Underlined text is an addition; strikethrough text is a deletion.)

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A096365 Maximum number of iterations of the RUNS transform needed to reduce any binary sequence of length n to a sequence of length 1.
(history; published version)
#5 by R. J. Mathar at Mon Oct 08 09:57:20 EDT 2018
STATUS

editing

approved

#4 by R. J. Mathar at Mon Oct 08 09:57:15 EDT 2018
CROSSREFS

Cf. A319412

STATUS

approved

editing

#3 by Russ Cox at Fri Mar 30 17:37:53 EDT 2012
AUTHOR

_John W. Layman (layman(AT)math.vt.edu), _, Jul 01 2004

Discussion
Fri Mar 30 17:37
OEIS Server: https://oeis.org/edit/global/182
#2 by N. J. A. Sloane at Sat Nov 10 03:00:00 EST 2007
COMMENTS

The RUNS transform maps a finite word (or sequence) x to the (finite) sequence y whose ithi-th term is the length of the ithi-th subsequence of consecutive identical terms of x. (Example: RUNS{1,2,2,2,1,1,3,3,1}={1,3,2,2,1})

KEYWORD

nonn,new

nonn

#1 by N. J. A. Sloane at Wed Sep 22 03:00:00 EDT 2004
NAME

Maximum number of iterations of the RUNS transform needed to reduce any binary sequence of length n to a sequence of length 1.

DATA

0, 2, 3, 4, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 9

OFFSET

1,2

COMMENTS

The RUNS transform maps a finite word (or sequence) x to the (finite) sequence y whose ith term is the length of the ith subsequence of consecutive identical terms of x. (Example: RUNS{1,2,2,2,1,1,3,3,1}={1,3,2,2,1})

EXAMPLE

The following example shows that a(21)>=9:

x={100110100100110110100}

RUNS(x)={12211212212112}

RUNS^2(x)={1221121121}

RUNS^3(x)={1221211}

RUNS^4(x)={12112}

RUNS^5(x)={1121}

RUNS^6(x)={211}

RUNS^7(x)={12}

RUNS^8(x)={11}

RUNS^9(x)={2}

Since calculation shows that no other binary sequence of length 21 requires more than 9 iterations of RUNS to reduce it to a single term, we have a(21)=9.

KEYWORD

nonn

AUTHOR

John W. Layman (layman(AT)math.vt.edu), Jul 01 2004

STATUS

approved

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Last modified August 30 21:28 EDT 2024. Contains 375550 sequences. (Running on oeis4.)