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 A196200 Numbers k such that Euler phi(Dedekind psi(k)) > k. 1
 39270, 53130, 71610, 78540, 82110, 106260, 108570, 117810, 122430, 143220, 157080, 159390, 164010, 164220, 212520, 214830, 217140, 235620, 244860, 246330, 247170, 286440, 293370, 314160, 318780, 325710, 328020, 328440, 353430, 367290, 425040, 429660, 434280 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Counterexamples to a conjecture by Sandor. LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..66 from Indranil Ghosh) Jozsef Sandor, On the Composition of Some Arithmetic Functions, II, Journal of Inequalities in Pure and Applied Mathematics (JIPAM), Volume 6, Issue 3, Article 73, 2005. MATHEMATICA Select[Range[39270, 434280], EulerPhi[# * Sum[MoebiusMu[d]^2 / d, {d, Divisors[#]}]] > # &] (* Indranil Ghosh, Mar 11 2017 *) PROG (PARI) a(m) = {for (n=1, m, if (eulerphi(n * sumdiv( n, d, moebius(d)^2 / d)) > n, print1(n, ", ")); ); } CROSSREFS Cf. A000010, A001615. Sequence in context: A233955 A250515 A031667 * A274128 A144306 A234033 Adjacent sequences: A196197 A196198 A196199 * A196201 A196202 A196203 KEYWORD nonn AUTHOR Michel Marcus, Dec 21 2012 STATUS approved

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Last modified May 19 19:45 EDT 2024. Contains 372703 sequences. (Running on oeis4.)