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A235060
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The greedy sequence of real numbers at least 1 that do not contain any 9-term geometric progressions with integer ratio.
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7
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1, 256, 512, 6561, 6912, 13824, 19683, 131072, 221184, 492075, 655360
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OFFSET
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1,2
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COMMENTS
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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, ar^7, ar^8} with r an integer.
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LINKS
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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
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CROSSREFS
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A235054 through A235060 give the greedy sets avoiding k-term geometric progressions for 3 <= k <= 9.
Sequence in context: A031465 A045081 A294153 * A260243 A206137 A206130
Adjacent sequences: A235057 A235058 A235059 * A235061 A235062 A235063
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KEYWORD
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nonn
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AUTHOR
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Kevin O'Bryant, Jan 03 2014
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STATUS
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approved
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