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Search: id:A073483
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| A073483 |
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For the n-th square-free number: the product of all primes greater its smallest factor, less its largest factor and not dividing it. |
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+0
5
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| 1, 1, 1, 1, 1, 1, 3, 1, 1, 15, 1, 1, 1, 5, 105, 1, 1155, 1, 1, 1, 35, 15015, 1, 1, 255255, 385, 1, 5, 1, 4849845, 1, 5005, 1, 7, 85085, 111546435, 1, 1, 3234846615, 77, 35, 1, 1616615, 1, 1, 1, 100280245065, 1, 3850, 1, 3710369067405, 1, 1001
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OFFSET
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1,7
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COMMENT
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a(n)=1 iff A073484(n)=0; a(A000040(n))=1, a(A006094(n))=1, a(A002110(n))=1.
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FORMULA
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a(n) = A002110(A073482(n))/(A005117(n)*A002110(A073481(n))).
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EXAMPLE
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The 69th square-free number is 110=2*5*11, primes between 2 and 11, not dividing 110, are 3 and 7, therefore a(69)=21.
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CROSSREFS
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Cf. A005117, A000040, A073484.
Sequence in context: A094573 A055154 A015112 this_sequence A006956 A072285 A110112
Adjacent sequences: A073480 A073481 A073482 this_sequence A073484 A073485 A073486
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KEYWORD
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nonn,nice
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Aug 03 2002
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