OFFSET
0,2
COMMENTS
Giving the sequence an offset of 1 instead and letting a(1)=1, we get the sequence beginning: 1,3,5,6,9,9,10,12,15,14,15,16,18,20,... This is the same sequence for every term from a(5) on.
EXAMPLE
a(10)=14 because a(9) (=15) has 4 positive divisors (1,3,5,15) and then a(10)=10+4=14.
MAPLE
with(numtheory): a[0]:=1: for n to 60 do a[n]:=n+tau(a[n-1]) end do: seq(a[n], n=0..60); # Emeric Deutsch, Nov 12 2007
MATHEMATICA
a = {1}; Do[AppendTo[a, Length[a] + Length[Divisors[a[[ -1]]]]], {70}]; a (* Stefan Steinerberger, Oct 30 2007 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Oct 28 2007
EXTENSIONS
More terms from Stefan Steinerberger, Oct 30 2007
STATUS
approved