A063989 Numbers with a prime number of prime divisors (counted with multiplicity).

4, 6, 8, 9, 10, 12, 14, 15, 18, 20, 21, 22, 25, 26, 27, 28, 30, 32, 33, 34, 35, 38, 39, 42, 44, 45, 46, 48, 49, 50, 51, 52, 55, 57, 58, 62, 63, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 82, 85, 86, 87, 91, 92, 93, 94, 95, 98, 99, 102, 105, 106

Offset: 1

Author

N. J. A. Sloane, Sep 18 2001

Keywords

• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Programs

Maple

with(numtheory); a := []: for i from 1 to 300 do if isprime(bigomega(i)) then a := [op(a),i]; fi; od: a;

Mathematica

Select[Range[200],PrimeQ[PrimeOmega[#]]&] (* Harvey P. Dale, Jul 25 2015 *)

PARI

n=0; for (m=1, 10^9, if (isprime(bigomega(m)), write("b063989.txt", n++, " ", m); if (n==1000, break))) \\ Harry J. Smith, Sep 05 2009

PARI

is(n)=isprime(bigomega(n)) \\ Charles R Greathouse IV, Sep 18 2015