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Search: id:A072747
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| A072747 |
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Counting factor 2 in square-free numbers <=n. |
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+0
5
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| 0, 1, 1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 11, 11, 11, 11, 11, 12, 12, 12, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16, 17, 17, 18, 18, 18, 19, 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 25, 25, 26, 26, 26
(list; graph; listen)
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OFFSET
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1,5
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EXAMPLE
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The first 10 square-free numbers are: 1, 2, 3, 5, 6=2*3, 7, 10=2*5, 11, 13 and 14=2*7
2, 6, 10 and 14 are divisible by 2, therefore a(10)=4.
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CROSSREFS
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Cf. A005117, A072748, A072749, A072750, A072751.
Sequence in context: A143824 A034463 A071996 this_sequence A124755 A033810 A023965
Adjacent sequences: A072744 A072745 A072746 this_sequence A072748 A072749 A072750
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 08 2002
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