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 A079534 a(n) = phi(n) - ceiling( (log 2 / 2) * (n / log n) ). 5
 0, 1, 1, 2, 0, 4, 2, 4, 2, 8, 2, 10, 4, 6, 6, 13, 3, 15, 5, 9, 7, 19, 5, 17, 9, 15, 9, 25, 4, 26, 12, 16, 12, 20, 8, 32, 14, 20, 12, 36, 8, 38, 15, 19, 17, 41, 11, 37, 15, 27, 19, 47, 13, 35, 19, 31, 23, 52, 10, 54, 24, 30, 26, 42, 14, 60, 26, 38, 18, 64, 18, 66, 30, 33, 29, 53, 17, 71, 25 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,4 COMMENTS It is known that a(n) >= 0. REFERENCES D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 9. LINKS G. C. Greubel, Table of n, a(n) for n = 2..10000 MATHEMATICA Table[EulerPhi[n] - Ceiling[n*Log[2.]/(2*Log[n])], {n, 2, 80}] (* G. C. Greubel, Jan 14 2019 *) PROG (PARI) vector(80, n, n++; eulerphi(n) - ceil(n*log(2.)/(2*log(n)))) \\ G. C. Greubel, Jan 14 2019 (MAGMA) [EulerPhi(n) - Ceiling(n*Log(2.)/(2*Log(n))): n in [2..80]]; // G. C. Greubel, Jan 14 2019 (Sage) [euler_phi(n) - ceil(n*log(2.)/(2*log(n))) for n in (2..80)] # G. C. Greubel, Jan 14 2019 CROSSREFS Cf. A000010, A079530, A079531, A079532, A079533. Sequence in context: A107490 A094572 A323905 * A229910 A097042 A332001 Adjacent sequences:  A079531 A079532 A079533 * A079535 A079536 A079537 KEYWORD nonn AUTHOR N. J. A. Sloane, Jan 23 2003 STATUS approved

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Last modified May 15 10:54 EDT 2021. Contains 343909 sequences. (Running on oeis4.)