OFFSET
1,2
COMMENTS
Always > 0 for n > 12.
REFERENCES
József Sándor, Dragoslav S. Mitrinovic, and Borislav Crstici, Handbook of Number Theory I, Springer Science & Business Media, 2005, Chapter III, p. 77, section III.1.1.c.
MATHEMATICA
a[n_] := Floor[n * Sqrt[n] / Zeta[2]] - DivisorSigma[1, n]; Array[a, 100] (* Amiram Eldar, Apr 23 2024 *)
PROG
(PARI) a(n)=6*n*sqrt(n)\Pi^2 - sigma(n) \\ Charles R Greathouse IV, Feb 14 2013
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Nov 29 2000
STATUS
approved