|
%I #14 May 13 2013 01:49:34
%S 6480,9072,14256,16848,22032,24624,29808,30000,37584,40176,47952,
%T 53136,55728,60912,68688,70000,76464,79056,86832,92016,94608,101250,
%U 102384,107568,110000,115248,115344,125712,130000,130896,133488,138672
%N Numbers with prime factorization pq^4r^4.
%H T. D. Noe, <a href="/A190012/b190012.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>
%t f[n_]:=Sort[Last/@FactorInteger[n]]=={1,4,4};Select[Range[250000],f]
%o (PARI) list(lim)=my(v=List(),t1,t2);forprime(p=2, (lim\2)^(1/8), t1=p^4;forprime(q=p+1, (lim\t1)^(1/4), t2=t1*q^4;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 Cf. A179665, A179668, A190011.
%K nonn
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, May 04 2011
|
