A139432 - OEIS

%I #12 Sep 12 2019 20:49:41

%S 0,1,3,1,4,2,6,4,0,3,7,5,11,9,5,1,6,4,10,8,2,6,2,0,8,5,1,5,11,9,1,3,9,

%T 5,1,5,14,12,8,4,12,10,2,0,6,0,4,2,12,9,3,7,1,3,11,7,15,11,7,5,17,15,

%U 11,5,12,8,0,2,8,4,12,10,22,20,16,10,4,0,8,6,16,11,7,5,17,13,9,5,13,11,23,19

%N a(0)=0. For n>=1, a(n) = a(n-1) - d(n) if a(n-1) >= d(n); a(n) = a(n-1) + d(n) if a(n-1) < d(n); where d(n) is the number of positive divisors of n.

%C a(A139433(n)) = 0.

%H N. J. A. Sloane, <a href="/A139432/b139432.txt">Table of n, a(n) for n = 0..10000</a>

%t Join[{a = 0}, Table[If[a < (x = DivisorSigma[0, n]), a += x, a -= x]; a, {n, 91}]] (* _Jayanta Basu_, Jun 06 2013 *)

%Y Cf. A139433.

%K nonn

%O 0,3

%A _Leroy Quet_, Apr 21 2008

%E More terms from _Sean A. Irvine_, Dec 02 2009