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A175952 The generations in which the transformation described in A072207 does not lead to a doubling of the cardinality of the set of rationals. 1
6, 12, 15, 18, 20, 21, 24 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..7.

FORMULA

By definition, this is {s: A072207(s) < 2*A072207(s-1)}. [R. J. Mathar, Oct 30 2010]

EXAMPLE

The set size in A072207 doubles with the first 5 transformations, 1->2->4->8->16->32. a(1)=6 because the 6th application grows the set only 32->52 (to less than 64).

CROSSREFS

Cf. A072207.

Sequence in context: A030659 A142338 A114304 * A278638 A208770 A219095

Adjacent sequences:  A175949 A175950 A175951 * A175953 A175954 A175955

KEYWORD

more,nonn

AUTHOR

Dylan Hamilton, Oct 28 2010

EXTENSIONS

Rewrote definition in terms of A072207. - R. J. Mathar Oct 30 2010

Edited by N. J. A. Sloane, Nov 24 2016

STATUS

approved

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Last modified February 23 00:28 EST 2020. Contains 332157 sequences. (Running on oeis4.)