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Search: id:A069087
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| A069087 |
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Numbers n such that (1/n)*sum(k=1,n,core(k))>phi(n) where core(n)=A007913(n) is the square-free part of n: the smallest number such that n*a(n) is a square, and phi(n)=A000010(n) is the Euler totient function. |
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+0
3
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| 2, 6, 12, 18, 24, 30, 36, 42, 48, 60, 66, 72, 78, 84, 90, 96, 102, 114, 120, 126, 132, 138, 144, 150, 156, 168, 174, 180, 186, 198, 204, 210, 222, 228, 234, 240, 246, 252, 258, 264, 270, 276, 282, 294, 300, 306, 312, 318, 330, 336, 342, 348, 360, 372, 378, 390
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OFFSET
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1,1
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COMMENT
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Equivalently, n such that A069891(n) > n*phi(n).
The listed terms are all even, but there are some odd terms, including n = 111546435 = 3*5*7*11*13*17*19*23, for which A069891(n)=4093453424286382 and n*phi(n) = 4070927302041600.
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CROSSREFS
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Sequence in context: A043343 A066080 A071707 this_sequence A085345 A032371 A108585
Adjacent sequences: A069084 A069085 A069086 this_sequence A069088 A069089 A069090
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KEYWORD
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nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 05 2002
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EXTENSIONS
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Edited by Dean Hickerson (dean(AT)math.ucdavis.edu), Apr 09 2002
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