A179688 Numbers of the form p^3*q^3*r where p, q, and r are prime.

1080, 1512, 2376, 2808, 3000, 3672, 4104, 4968, 6264, 6696, 6750, 7000, 7992, 8232, 8856, 9288, 10152, 11000, 11448, 12744, 13000, 13176, 13720, 14472, 15336, 15768, 17000, 17064, 17928, 18522, 19000, 19224, 20952, 21816, 22248, 23000, 23112

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, Jul 24 2010

Keywords

• nonn

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000
• Will Nicholes, Prime Signatures
• Index to sequences related to prime signature

Programs

Mathematica

f[n_]:=Sort[Last/@FactorInteger[n]]=={1,3,3}; Select[Range[20000], f]

PARI

list(lim)=my(v=List(),t1,t2);forprime(p=2, (lim\2)^(1/6), t1=p^3;forprime(q=p+1, (lim\t1)^(1/3), t2=t1*q^3;forprime(r=2, lim\t2, if(p==r||q==r, next);listput(v,t2*r)))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Jul 20 2011