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A190467 Numbers with prime factorization pq^3r^6. 4

%I #10 May 13 2013 01:49:35

%S 8640,12096,19008,22464,24000,29160,29376,32832,39744,40824,50112,

%T 53568,56000,63936,64152,65856,70848,74304,75816,81216,88000,91584,

%U 99144,101952,104000,105408,109760,110808,115776,122688,126144,134136,136000

%N Numbers with prime factorization pq^3r^6.

%H T. D. Noe, <a href="/A190467/b190467.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]]=={1,3,6}; Select[Range[200000],f]

%o (PARI) list(lim)=my(v=List(),t1,t2);forprime(p=2, (lim\24)^(1/6), t1=p^6;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

%Y Cf. A179747, A190465, A190466.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, May 10 2011

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Last modified August 4 08:46 EDT 2024. Contains 374906 sequences. (Running on oeis4.)