cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A190380 Numbers with prime factorization pqrst^2u^2.

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%I A190380 #11 May 20 2017 11:46:24
%S A190380 180180,235620,263340,278460,300300,311220,318780,376740,392700,
%T A190380 401940,406980,420420,429660,437580,438900,450450,464100,475020,
%U A190380 489060,492660,507780,512820,518700,531300,549780,550620,568260,589050,592020,595980
%N A190380 Numbers with prime factorization pqrst^2u^2.
%H A190380 T. D. Noe, <a href="/A190380/b190380.txt">Table of n, a(n) for n = 1..1000</a>
%H A190380 Will Nicholes, <a href="http://willnicholes.com/math/primesiglist.htm">Prime Signatures</a>
%H A190380 <a href="/index/Pri#prime_signature">Index to sequences related to prime signature</a>
%t A190380 f[n_]:=Sort[Last/@FactorInteger[n]]=={1,1,1,1,2,2};Select[Range[1000000],f]
%o A190380 (PARI) list(lim)=my(v=List(),t1,t2,t3,t4,t5); forprime(p=2,sqrtint(lim\4620), t1=p^2; forprime(q=2,sqrtint(lim\(210*t1)), if(q==p, next); t2=q^2*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 A190380 Cf. A190378, A190379.
%K A190380 nonn
%O A190380 1,1
%A A190380 _Vladimir Joseph Stephan Orlovsky_, May 09 2011