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A057627
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Number of nonsquarefree numbers not exceeding n.
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4
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0, 0, 0, 1, 1, 1, 1, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 6, 6, 7, 7, 7, 7, 8, 9, 9, 10, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 15, 16, 16, 16, 17, 18, 19, 19, 20, 20, 21, 21, 22, 22, 22, 22, 23, 23, 23, 24, 25, 25, 25, 25, 26, 26, 26, 26, 27, 27, 27, 28, 29, 29, 29
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,8
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COMMENTS
| Asymptotic to (1 - 1 / zeta(2)) * n = (1 - 6 / pi^2) * n. - Daniel Forgues, Jan 28 2011
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FORMULA
| a(n)=n-A013928(n)=n-Sum(Moebius(k)^2, k=1, ..n)
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EXAMPLE
| a(36)=13 because 13 not-squarefree numbers exist which do not exceed 36:{4,8,9,12,16,18,20,24,25,27,28,32,36}. This sequence is different from A013940, albeit the first 35 terms are identical.
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CROSSREFS
| Cf. A008683, A013940, A013928, A002321, A028442.
Sequence in context: A106742 A106733 A087838 * A013940 A029129 A087842
Adjacent sequences: A057624 A057625 A057626 * A057628 A057629 A057630
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Oct 10 2000
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