A079534 a(n) = phi(n) - ceiling( (log 2 / 2) * (n / log n) ).

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

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