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A079546 a(n) = sigma(n) - 4*phi(n). 1
-3, -1, -4, -1, -10, 4, -16, -1, -11, 2, -28, 12, -34, 0, -8, -1, -46, 15, -52, 10, -16, -4, -64, 28, -49, -6, -32, 8, -82, 40, -88, -1, -32, -10, -48, 43, -106, -12, -40, 26, -118, 48, -124, 4, -18, -16, -136, 60, -111, 13, -56, 2, -154, 48, -88, 24, -64, -22, -172, 104, -178, -24, -40, -1, -108, 64, -196, -2, -80, 48, -208, 99, -214 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 88.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

MATHEMATICA

Table[DivisorSigma[1, n]-4*EulerPhi[n], {n, 80}] (* Harvey P. Dale, Dec 08 2014 *)

PROG

(PARI) vector(80, n, sigma(n) - 4*eulerphi(n)) \\ G. C. Greubel, Jun 19 2019

(MAGMA) [DivisorSigma(1, n) - 4*EulerPhi(n): n in [1..80]]; // G. C. Greubel, Jun 19 2019

(Sage) [sigma(n, 1) - 4*euler_phi(n) for n in (1..80)] # G. C. Greubel, Jun 19 2019

CROSSREFS

Cf. A000010, A000203, A068390.

Sequence in context: A318841 A300238 A180062 * A014413 A262072 A321743

Adjacent sequences:  A079543 A079544 A079545 * A079547 A079548 A079549

KEYWORD

sign,changed

AUTHOR

N. J. A. Sloane, Jan 23 2003

STATUS

approved

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Last modified June 19 19:11 EDT 2019. Contains 324222 sequences. (Running on oeis4.)