A046390 Squarefree odd numbers with exactly 4 distinct prime factors.
1155, 1365, 1785, 1995, 2145, 2415, 2805, 3003, 3045, 3135, 3255, 3315, 3705, 3795, 3885, 3927, 4305, 4389, 4485, 4515, 4641, 4785, 4845, 4935, 5005, 5115, 5187, 5313, 5565, 5655, 5865, 6045, 6105, 6195, 6279, 6405, 6545, 6555, 6699, 6765, 6783, 7035
Offset: 1
Keywords
Links
- T. D. Noe, Table of n, a(n) for n=1..1000
Programs
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Mathematica
f[n_]:=Last/@FactorInteger[n]=={1,1,1,1}&&FactorInteger[n][[1,1]]>2; lst={};Do[If[f[n],AppendTo[lst,n]],{n,8!}];lst (* Vladimir Joseph Stephan Orlovsky, Nov 23 2009 *) Select[Range[1,8001,2],PrimeNu[#]==PrimeOmega[#]==4&] (* Harvey P. Dale, Mar 28 2013 *) -
PARI
list(lim)=my(v=List()); forprime(p=3,sqrtnint(lim\=1,4), forprime(q=p+2,sqrtnint(lim\p,3), forprime(r=q+2,sqrtint(lim\p\q), my(t=p*q*r); forprime(s=r+2,lim\t, listput(v,t*s))))); Set(v) \\ Charles R Greathouse IV, Dec 06 2024