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 A286266 Number of totient abundant numbers <= 10^n. 0
 2, 36, 383, 3708, 35731, 347505, 3407290, 33579303 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Totient abundant numbers are defined in A286265. a(3)-a(8) were calculated by Loomis & Luca (2008). LINKS Paul Loomis and Florian Luca, On totient abundant numbers, Electronic Journal of Combinatorial Number Theory, Vol. 8, #A06 (2008). EXAMPLE There are 2 totient abundant numbers <= 10^1 (5 and 7), thus a(1)=2. MATHEMATICA 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 *) CROSSREFS Cf. A000010, A082897, A092693, A286265. Sequence in context: A119582 A157055 A057407 * A193127 A092852 A139738 Adjacent sequences:  A286263 A286264 A286265 * A286267 A286268 A286269 KEYWORD nonn,more AUTHOR Amiram Eldar, May 05 2017 STATUS approved

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Last modified August 18 09:28 EDT 2022. Contains 356204 sequences. (Running on oeis4.)