A062968 n + 1 - d(n), where d(n) is the number of divisors function.

1, 1, 2, 2, 4, 3, 6, 5, 7, 7, 10, 7, 12, 11, 12, 12, 16, 13, 18, 15, 18, 19, 22, 17, 23, 23, 24, 23, 28, 23, 30, 27, 30, 31, 32, 28, 36, 35, 36, 33, 40, 35, 42, 39, 40, 43, 46, 39, 47, 45, 48, 47, 52, 47, 52, 49, 54, 55, 58, 49, 60, 59, 58, 58, 62, 59, 66, 63, 66, 63, 70, 61, 72

Offset: 1

Author

Jason Earls, Jul 23 2001

Keywords

• nonn

Comments

A062968 = n - A070824 [From Eric Desbiaux, Dec 10 2009]

Crossrefs

Cf. A062969.

Cf. A000005, A049820. [From Omar E. Pol, Jul 16 2009]

Programs

Mathematica

Table[n + 1 - DivisorSigma[0, n], {n, 1, 73}] (* Jean-François Alcover, Jun 24 2013 *)

PARI

j=[]; for(n=1,150,j=concat(j,numdiv(n)-n-1)); j

Formula

a(n) = n+1-A000005(n) = A049820(n)-1. [From Omar E. Pol, Jul 16 2009]