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A063989 Numbers with a prime number of prime divisors (counted with multiplicity). 13

%I #11 Sep 18 2015 14:00:39

%S 4,6,8,9,10,12,14,15,18,20,21,22,25,26,27,28,30,32,33,34,35,38,39,42,

%T 44,45,46,48,49,50,51,52,55,57,58,62,63,65,66,68,69,70,72,74,75,76,77,

%U 78,80,82,85,86,87,91,92,93,94,95,98,99,102,105,106

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

%H Harry J. Smith, <a href="/A063989/b063989.txt">Table of n, a(n) for n = 1..1000</a>

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

%t Select[Range[200],PrimeQ[PrimeOmega[#]]&] (* _Harvey P. Dale_, Jul 25 2015 *)

%o (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

%o (PARI) is(n)=isprime(bigomega(n)) \\ _Charles R Greathouse IV_, Sep 18 2015

%K nonn

%O 1,1

%A _N. J. A. Sloane_, Sep 18 2001

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Last modified April 24 15:57 EDT 2024. Contains 371961 sequences. (Running on oeis4.)