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A286266
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Number of totient abundant numbers <= 10^n.
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0
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OFFSET
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1,1
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COMMENTS
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Totient abundant numbers are defined in A286265.
a(3)-a(8) were calculated by Loomis & Luca (2008).
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LINKS
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Table of n, a(n) for n=1..8.
Paul Loomis and Florian Luca, On totient abundant numbers, Electronic Journal of Combinatorial Number Theory, Vol. 8, #A06 (2008).
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EXAMPLE
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There are 2 totient abundant numbers <= 10^1 (5 and 7), thus a(1)=2.
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MATHEMATICA
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Accumulate@ Table[Count[Select[Range[10^(n - 1) + 1, 10^n], (Total@ FixedPointList[EulerPhi, #] - (# + 1)) > # &], k_ /; k <= 10^n], {n, 6}] (* Michael De Vlieger, May 06 2017, after Alonso del Arte at A092693 *)
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CROSSREFS
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Cf. A000010, A082897, A092693, A286265.
Sequence in context: A119582 A157055 A057407 * A193127 A092852 A139738
Adjacent sequences: A286263 A286264 A286265 * A286267 A286268 A286269
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KEYWORD
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nonn,more
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AUTHOR
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Amiram Eldar, May 05 2017
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STATUS
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approved
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