A069345 n minus the number of its prime-factors: a(n) = n - A001222(n).

1, 1, 2, 2, 4, 4, 6, 5, 7, 8, 10, 9, 12, 12, 13, 12, 16, 15, 18, 17, 19, 20, 22, 20, 23, 24, 24, 25, 28, 27, 30, 27, 31, 32, 33, 32, 36, 36, 37, 36, 40, 39, 42, 41, 42, 44, 46, 43, 47, 47, 49, 49, 52, 50, 53, 52, 55, 56, 58, 56, 60, 60, 60, 58, 63, 63, 66, 65

Offset: 1

Author

Reinhard Zumkeller, Mar 18 2002

Keywords

• nonn
• easy
• changed

Comments

Prime factors are counted with multiplicity. - Harvey P. Dale, Sep 20 2011

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A001222, A064800, A069355.

Programs

Magma

[n eq 1 select 1 else n-(&+[p[2]: p in Factorization(n)]): n in [1..100]]; // Vincenzo Librandi, Apr 09 2018

Mathematica

Table[n-PrimeOmega[n],{n,70}] (* Harvey P. Dale, Sep 20 2011 *)

PARI

a(n) = n - bigomega(n); \\ Michel Marcus, Apr 08 2018