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A096916 Lesser prime factor of n-th product of two distinct primes.

%I A096916 #17 Sep 14 2015 11:41:48
%S A096916 2,2,2,3,3,2,2,3,2,5,2,3,2,3,5,3,2,2,5,3,2,7,2,5,2,3,7,3,2,5,2,3,5,2,
%T A096916 7,2,3,3,7,2,3,2,11,5,2,5,2,3,7,2,3,2,3,5,11,2,3,2,7,5,2,11,3,2,5,7,2,
%U A096916 3,13,2,5,3,13,3,11,2,7,2,5,3,2,2,7,3,5,2,13,7,2,3,5,3,2,11,3,17,2,3
%N A096916 Lesser prime factor of n-th product of two distinct primes.
%C A096916 a(n)*A070647(n) = A006881(n); a(n) < A070647(n);
%C A096916 a(n) = A020639(A006881(n)).
%H A096916 Reinhard Zumkeller, <a href="/A096916/b096916.txt">Table of n, a(n) for n = 1..10000</a>
%t A096916 f[n_]:=Last/@FactorInteger[n]=={1,1};f1[n_]:=Min[First/@FactorInteger[n]];f2[n_]:=Max[First/@FactorInteger[n]];lst={};Do[If[f[n],AppendTo[lst,f1[n]]],{n,0,6!}];lst (* _Vladimir Joseph Stephan Orlovsky_, Apr 10 2010 *)
%o A096916 (Haskell)
%o A096916 a096916 = a020639 . a006881 -- _Reinhard Zumkeller_, Sep 23 2011
%o A096916 (PARI) go(x)=my(v=List()); forprime(p=2, sqrtint(x\1), forprime(q=p+1, x\p, listput(v, [p*q,p]))); apply(v->v[2], vecsort(Vec(v),1)) \\ _Charles R Greathouse IV_, Sep 14 2015
%Y A096916 Cf. A084126, A195758.
%K A096916 nonn,look
%O A096916 1,1
%A A096916 _Reinhard Zumkeller_, Jul 15 2004