A067028 - OEIS

%I #15 Dec 09 2024 10:13:11

%S 16,24,36,40,54,56,60,64,81,84,88,90,96,100,104,126,132,135,136,140,

%T 144,150,152,156,160,184,189,196,198,204,210,216,220,224,225,228,232,

%U 234,240,248,250,256,260,276,294,296,297,306,308,315,324,328,330,336

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

%H Harry J. Smith, <a href="/A067028/b067028.txt">Table of n, a(n) for n = 1..1000</a>

%e a(1)=16, 16 has 4 prime factors (counted with multiplicity) and 4 is composite.

%o (PARI) is(n)=my(t=bigomega(n)); t>1 && !isprime(t) \\ _Charles R Greathouse IV_, Oct 15 2015

%Y Cf. A063989.

%K nonn

%O 1,1

%A _Shyam Sunder Gupta_, Feb 16 2002