login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A235057 The greedy sequence of real numbers at least 1 that do not contain any 6-term geometric progressions with integer ratio. 0
1, 32, 64, 243, 288, 576, 729, 1152, 2048, 3645, 4000, 10240, 20736, 21952, 92160, 100000, 102400, 207360, 219520, 518400, 548800, 921600 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The union of the half-open intervals [a(2i-1),a(2i)) is the greedy set of real numbers at least 1 that does not contain any subset of the form {a, ar, ar^2, ar^3, ar^4, ar^5} with r an integer.

LINKS

Table of n, a(n) for n=1..22.

M. B. Nathanson, K. O'Bryant, A problem of Rankin on sets without geometric progressions, arXiv preprint arXiv:1408.2880, 2014

CROSSREFS

A235054 through A235060 give the greedy sets avoiding k-term geometric progressions for 3 <= k <= 9.

Sequence in context: A069492 A076469 A256819 * A249116 A110562 A275187

Adjacent sequences:  A235054 A235055 A235056 * A235058 A235059 A235060

KEYWORD

nonn,more

AUTHOR

Kevin O'Bryant, Jan 03 2014

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 6 15:25 EDT 2020. Contains 334827 sequences. (Running on oeis4.)