1,2

G. C. Greubel, Table of n, a(n) for n = 1..1000

a(n) = A000203(n) - A029837(n).

a(1) = 1 - 0 = 1;

a(2) = 3 - 1 = 2;

a(3) = 4 - 2 = 3.

Table[DivisorSigma[1, n] - Ceiling[Log[2, n]], {n, 100}] (* G. C. Greubel, Dec 18 2016 *)

Cf. A000203 (sum of divisors), A029837 (binary order).

Sequence in context: A075545 A006307 A152991 * A133440 A331520 A160793

Adjacent sequences: A163295 A163296 A163297 * A163299 A163300 A163301

nonn,less

Juri-Stepan Gerasimov, Jul 25 2009

Entries checked by R. J. Mathar, May 21 2010

approved