A190379 Numbers with prime factorization pqr^2s^2t^2.

69300, 81900, 97020, 107100, 114660, 119700, 128700, 144900, 149940, 152460, 161700, 167580, 168300, 182700, 188100, 191100, 195300, 198900, 202860, 212940, 222300, 227700, 233100, 242550, 249900, 252252, 254100, 255780, 258300, 269100

Offset: 1

Author

Vladimir Joseph Stephan Orlovsky, May 09 2011

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

Crossrefs

Cf. A190110, A190111.

Programs

Mathematica

f[n_]:=Sort[Last/@FactorInteger[n]]=={1,1,2,2,2};Select[Range[600000],f]

PARI

list(lim)=my(v=List(),t1,t2,t3,t4); forprime(p=2,sqrtint(lim\1260), t1=p^2; forprime(q=2,sqrtint(lim\(60*t1)), if(q==p, next); t2=q^2*t1; forprime(r=2,sqrtint(lim\(6*t2)), if(r==p || r==q, next); t3=r^2*t2; forprime(s=2,lim\(2*t3), if(s==p || s==q || s==r, next); t4=s*t3; forprime(t=2,lim\t4, if(t==p || t==q || t==r || t==s, next); listput(v, t4*t)))))); Set(v) \\ Charles R Greathouse IV, Aug 25 2016