Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #21 Mar 05 2024 11:26:23
%S 1440,2016,2400,3168,3744,4704,4860,4896,5472,5600,6624,6804,7840,
%T 8352,8800,8928,10400,10656,10692,11616,11808,12150,12384,12636,13536,
%U 13600,15200,15264,16224,16524,16992,17248,17568,18400,18468,19296,19360
%N Numbers p^5*q^2*r where p, q, r are 3 distinct primes.
%H T. D. Noe, <a href="/A179691/b179691.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]]=={1,2,5}; Select[Range[20000], f]
%o (PARI) list(lim)=my(v=List(),t1,t2);forprime(p=2, (lim\12)^(1/5), t1=p^5;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 24 2011
%Y Part of the list A178739 .. A179696 (and A030514 .. A030629, A189982 .. A189990 etc, cf. A101296). - _M. F. Hasler_, Jul 17 2019
%Y Subsequence of A175746 (numbers with 36 divisors).
%K nonn
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, Jul 24 2010
%E Name improved by _M. F. Hasler_, Jul 17 2019