A190012 Numbers with prime factorization pq^4r^4.

6480, 9072, 14256, 16848, 22032, 24624, 29808, 30000, 37584, 40176, 47952, 53136, 55728, 60912, 68688, 70000, 76464, 79056, 86832, 92016, 94608, 101250, 102384, 107568, 110000, 115248, 115344, 125712, 130000, 130896, 133488, 138672

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, May 04 2011

Keywords

• nonn

Links

• T. D. Noe, Table of n, a(n) for n = 1..1000
• Will Nicholes, Prime Signatures

Crossrefs

Cf. A179665, A179668, A190011.

Programs

Mathematica

f[n_]:=Sort[Last/@FactorInteger[n]]=={1,4,4};Select[Range[250000],f]

PARI

list(lim)=my(v=List(),t1,t2);forprime(p=2, (lim\2)^(1/8), t1=p^4;forprime(q=p+1, (lim\t1)^(1/4), t2=t1*q^4;forprime(r=2, lim\t2, if(p==r||q==r, next);listput(v,t2*r)))); vecsort(Vec(v)) \\ Charles R Greathouse IV, Jul 24 2011