A190473 Numbers with prime factorization pqrs^7.

13440, 21120, 24960, 29568, 32640, 34944, 36480, 44160, 45696, 49280, 51072, 54912, 55680, 58240, 59520, 61824, 71040, 71808, 76160, 77952, 78720, 80256, 82560, 83328, 84864, 85120, 90240, 91520, 94848, 97152, 99456, 101760, 103040, 110208

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, May 10 2011

Keywords

• nonn

Links

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

Crossrefs

Cf. A190470, A190471, A190472.

Programs

Mathematica

f[n_]:=Sort[Last/@FactorInteger[n]]=={1,1,1,7}; Select[Range[150000],f]

PARI

list(lim)=my(v=List(),t1,t2,t3); forprime(p=2,sqrtnint(lim\30, 7), t1=p^7; forprime(q=2,lim\(6*t1), if(q==p, next); t2=q*t1; forprime(r=2,lim\(2*t2), if(r==p || r==q, next); t3=r*t2; forprime(s=2,lim\t3, if(s==p || s==q || s==r, next); listput(v, t3*s))))); Set(v) \\ Charles R Greathouse IV, Aug 25 2016