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A189984 Numbers with prime factorization pqrst^3. 3

%I #11 May 20 2017 11:31:49

%S 9240,10920,14280,15960,17160,19320,20790,22440,24024,24360,24570,

%T 25080,26040,26520,29640,30360,31080,31416,32130,34440,35112,35880,

%U 35910,36120,37128,38280,38610,38760,39480,40040,40920,41496,42504,43470

%N Numbers with prime factorization pqrst^3.

%H T. D. Noe, <a href="/A189984/b189984.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]]=={1,1,1,1,3}; Select[Range[80000],f]

%o (PARI) list(lim)=my(v=List(),t1,t2,t3,t4); forprime(p=2,sqrtnint(lim\210, 3), t1=p^3; forprime(q=2,lim\(30*t1), if(q==p, next); t2=q*t1; forprime(r=2,lim\(6*t2), if(r==p || r==q, next); t3=r*t2; forprime(s=2,lim\(2*t3), if(s==p || s==q || s==r, next); t4=s*t3; forprime(t=2,lim\t4, if(t==p || t==q || t==r || t==s, next); listput(v, t4*t)))))); Set(v) \\ _Charles R Greathouse IV_, Aug 25 2016

%Y Cf. A179667, A179693.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, May 03 2011

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Last modified April 24 16:34 EDT 2024. Contains 371961 sequences. (Running on oeis4.)