A235058 The greedy sequence of real numbers at least 1 that do not contain any 7-term geometric progressions with integer ratio.

1, 64, 128, 1152, 1728, 8192, 28800, 172800, 248832, 307328, 395136

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, ar^6} with r an integer.

Links

Table of n, a(n) for n=1..11.

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: A256820 A031464 A045076 * A366287 A252088 A211254

Adjacent sequences: A235055 A235056 A235057 * A235059 A235060 A235061

Keyword

nonn,more

Author

Kevin O'Bryant, Jan 03 2014

Status

approved