OFFSET
0,1
COMMENTS
See A003415 for the definition of the arithmetic derivative.
MATHEMATICA
dn[0] = 0; dn[1] = 0; dn[n_?Negative] := -dn[-n]; dn[n_] := Module[{f = Transpose[FactorInteger[n]]}, If[PrimeQ[n], 1, Total[n*f[[2]]/f[[1]]]]]; s = 4^5; Join[{s}, Table[s = dn[s], {19}]] (* T. D. Noe, Mar 07 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Franz Tolosa, Mar 07 2013
STATUS
approved