A079540 a(n) = phi(n) + d(n)*(n - phi(n)) - sigma(n).

0, 0, 0, 1, 0, 6, 0, 5, 2, 10, 0, 24, 0, 14, 12, 17, 0, 39, 0, 38, 16, 22, 0, 76, 4, 26, 14, 52, 0, 112, 0, 49, 24, 34, 20, 137, 0, 38, 28, 118, 0, 156, 0, 80, 72, 46, 0, 212, 6, 107, 36, 94, 0, 186, 28, 160, 40, 58, 0, 376, 0, 62, 94, 129, 32, 244, 0, 122, 48, 248, 0, 405, 0, 74, 126

Offset

1,6

Comments

It is known that a(n) >= 0 for n >= 1.

References

D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 10.

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Mathematica

Array[#2 + #3 (#1 - #2) - #4 & @@ {#, EulerPhi@ #, DivisorSigma[0, #], DivisorSigma[1, #]} &, 75] (* Michael De Vlieger, Feb 25 2018 *)

Prog

(PARI) A079540(n) = (eulerphi(n) + numdiv(n)*(n - eulerphi(n)) - sigma(n)); \\ Antti Karttunen, Feb 25 2018
(Magma) [EulerPhi(n) + DivisorSigma(0, n)*(n - EulerPhi(n)) - DivisorSigma(1, n): n in [1..80]]; // G. C. Greubel, Jan 15 2019
(Sage) [euler_phi(n) + sigma(n, 0)*(n - euler_phi(n)) - sigma(n, 1) for n in (1..80)] # G. C. Greubel, Jan 15 2019

Crossrefs

Cf. A000010, A000005, A000203.

Sequence in context: A021627 A257580 A275933 * A011492 A274419 A131329

Adjacent sequences: A079537 A079538 A079539 * A079541 A079542 A079543

Keyword

nonn

Author

N. J. A. Sloane, Jan 23 2003

Status

approved