A200511 Numbers n with omega(n)=2 and bigomega(n)>2, where omega=A001221=number of distinct prime factors, bigomega=A001222=prime factors counted with multiplicity.

12, 18, 20, 24, 28, 36, 40, 44, 45, 48, 50, 52, 54, 56, 63, 68, 72, 75, 76, 80, 88, 92, 96, 98, 99, 100, 104, 108, 112, 116, 117, 124, 135, 136, 144, 147, 148, 152, 153, 160, 162, 164, 171, 172, 175, 176, 184, 188, 189, 192, 196, 200, 207, 208, 212, 216, 224, 225, 232, 236

Offset: 1

Author

M. F. Hasler, Feb 09 2012

Keywords

• nonn

Comments

Equivalently, numbers of the form n=p^k*q^m where k,m>0, k+m>2 and p,q prime.

It appears that this is equal to A123711.

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A200521, A178212.

Programs

Mathematica

Select[Range[240], PrimeNu[#] == 2 && PrimeOmega[#] > 2 &] (* Jean-François Alcover, Jun 29 2013 *)

PARI

for(n=1,999,bigomega(n)>2 & omega(n)==2 & print1(n","))