A179698 - OEIS

%I #10 May 20 2017 11:55:48

%S 2160,3024,3240,4536,4752,5616,6000,7128,7344,8208,8424,9936,11016,

%T 12312,12528,13392,14000,14904,15000,15984,16464,17712,18576,18792,

%U 20088,20250,20304,22000,22896,23976,25488,26000,26352,26568,27440

%N Numbers of the form p^4*q^3*r where p, q, and r are distinct primes.

%H T. D. Noe, <a href="/A179698/b179698.txt">Table of n, a(n) for n = 1..1000</a>

%H Will Nicholes, <a href="http://willnicholes.com/math/primesiglist.htm">Prime Signatures</a>

%H <a href="/index/Pri#prime_signature">Index to sequences related to prime signature</a>

%t f[n_]:=Sort[Last/@FactorInteger[n]]=={1,3,4}; Select[Range[30000], f]

%o (PARI) list(lim)=my(v=List(),t1,t2);forprime(p=2, (lim\24)^(1/4), t1=p^4;forprime(q=2, (lim\t1)^(1/3), if(p==q, next);t2=t1*q^3;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

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jul 24 2010