This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A163569 Numbers of the form p^3*q^2*r where p, q and r are three distinct primes. 4
 360, 504, 540, 600, 756, 792, 936, 1176, 1188, 1224, 1350, 1368, 1400, 1404, 1500, 1656, 1836, 1960, 2052, 2088, 2200, 2232, 2250, 2484, 2600, 2646, 2664, 2904, 2952, 3096, 3132, 3348, 3384, 3400, 3500, 3800, 3816, 3996, 4056, 4116, 4248, 4312, 4392 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS There is no constraint on which of the three primes is the largest or smallest. Subsequence of A137487. - R. J. Mathar, Aug 01 2009 LINKS T. D. Noe, Table of n, a(n) for n = 1..1000 EXAMPLE 360=2^3*3^2*5. 504=2^3*3^2*7. 1188=2^2*3^3*11. MATHEMATICA f[n_]:=Sort[Last/@FactorInteger[n]]=={1, 2, 3}; Select[Range[5000], f] PROG (PARI) list(lim)=my(v=List(), t1, t2); forprime(p=2, (lim\12)^(1/3), t1=p^3; forprime(q=2, sqrt(lim\t1), if(p==q, next); t2=t1*q^2; 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 CROSSREFS Sequence in context: A069478 A060665 A072414 * A063067 A076205 A048978 Adjacent sequences:  A163566 A163567 A163568 * A163570 A163571 A163572 KEYWORD nonn AUTHOR Vladimir Joseph Stephan Orlovsky, Jul 31 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.