A175952 The generations in which the transformation described in A072207 does not lead to a doubling of the cardinality of the set of rationals.

6, 12, 15, 18, 20, 21, 24

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