OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..10000
EXAMPLE
1*1'+2*2'+3*3'=0+2+3=5 ->a(3)= 5.
MAPLE
der:=n->n*add(op(2, p)/op(1, p), p=ifactors(n)[2]):
seq(add(der(i)*i, i=1..n), n=1..50);
MATHEMATICA
A003415[n_]:= If[Abs@n < 2, 0, n Total[#2/#1 & @@@FactorInteger[Abs@n]]];
Table[Sum[k*A003415[k], {k, 1, n}], {n, 1, 50}] (* G. C. Greubel, Dec 29 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Giorgio Balzarotti, May 04 2011
STATUS
approved