A152993 a(n) = n - d(n) - pi(n) + 1.

1, 0, 0, 0, 1, 0, 2, 1, 3, 3, 5, 2, 6, 5, 6, 6, 9, 6, 10, 7, 10, 11, 13, 8, 14, 14, 15, 14, 18, 13, 19, 16, 19, 20, 21, 17, 24, 23, 24, 21, 27, 22, 28, 25, 26, 29, 31, 24, 32, 30, 33, 32, 36, 31, 36, 33, 38, 39, 41, 32, 42, 41, 40, 40, 44, 41, 47, 44, 47, 44

Offset: 1

Author

Omar E. Pol, Dec 19 2008

Keywords

• easy
• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000005, A000720, A152770, A152991, A152992.

Programs

Mathematica

Table[n-DivisorSigma[0,n]-PrimePi[n]+1,{n,70}] (* Harvey P. Dale, Sep 16 2020 *)

PARI

a(n) = {n - numdiv(n) - primepi(n) + 1} \\ Andrew Howroyd, Jan 03 2020

Formula

a(n) = n - A000005(n) - A000720(n) + 1.

Extensions

Terms a(17) and beyond from Andrew Howroyd, Jan 03 2020