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A189985 Numbers with prime factorization pqrstu^2. 2


%S 60060,78540,87780,90090,92820,103740,106260,117810,125580,131670,

%T 133980,135660,139230,143220,145860,150150,155610,158340,159390,

%U 163020,164220,169260,170940,183540,188370,189420,196350,197340,198660,200970

%N Numbers with prime factorization pqrstu^2.

%H T. D. Noe, <a href="/A189985/b189985.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]]=={1,1,1,1,1,2}; Select[Range[300000],f]

%o (PARI) list(lim)=my(v=List(),t1,t2,t3,t4,t5); forprime(p=2,sqrtint(lim\2310), t1=p^2; forprime(q=2,lim\(210*t1), if(q==p, next); t2=q*t1; forprime(r=2,lim\(30*t2), if(r==p || r==q, next); t3=r*t2; forprime(s=2,lim\(6*t3), if(s==p || s==q || s==r, next); t4=s*t3; forprime(t=2,lim\(2*t4), if(t==p || t==q || t==r || t==s, next); t5=t*t4; forprime(u=2,lim\t5, if(u==p || u==q || u==r || u==s || u==t, next); listput(v, t5*u))))))); Set(v) \\ _Charles R Greathouse IV_, Aug 25 2016

%Y Cf. A179693, A189984.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, May 03 2011

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Last modified June 2 17:02 EDT 2020. Contains 334787 sequences. (Running on oeis4.)