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A327469
Number of nonempty subsets of [1..n] which are geometric progressions of length >= 3 with rational ratio and are locally maximal.
2
0, 0, 0, 1, 1, 1, 1, 1, 3, 3, 3, 4, 4, 4, 4, 5, 5, 7, 7, 8, 8, 8, 8, 8, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 19, 19, 19, 19, 19, 19, 19, 19, 20, 22, 22, 22, 23, 29, 33, 33, 34, 34, 34, 34, 34, 34, 34, 34, 35, 35, 35, 37, 40, 40, 40, 40, 41, 41, 41, 41, 45, 45, 45, 49, 50, 50, 50, 50, 51, 55, 55, 55, 56, 56, 56, 56, 56, 56, 58, 58, 59, 59, 59, 59, 60, 60, 66, 68, 77
OFFSET
1,9
COMMENTS
Exceptionally, DATA section give first 100 terms.
One might have expected that the GP would be required to have an integer ratio, but in fact we allow rational ratios. The GPs can be assumed to be increasing.
CROSSREFS
Sequence in context: A134849 A096056 A050501 * A105590 A220845 A361469
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 03 2019, using data computed by Rob Pratt.
STATUS
approved