OFFSET
1,8
COMMENTS
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
FORMULA
Sum_{k=1..n} a(k) ~ c * n^2, where c = (A136141 - A013661 + 1) / 2 = 0.0641113... . - Amiram Eldar, Mar 17 2024
MATHEMATICA
dn[0] = 0; dn[1] = 0; dn[n_?Negative] := -dn[-n]; dn[n_] := Module[{f = Transpose[FactorInteger[n]]}, If[PrimeQ[n], 1, Plus @@ (n*f[[2]]/f[[1]])]]; Table[dn[n] - (DivisorSigma[1, n] - n), {n, 100}] (* T. D. Noe, Dec 27 2012 *)
PROG
CROSSREFS
KEYWORD
sign
AUTHOR
Omar E. Pol, Dec 18 2012
STATUS
approved