

A096916


Lesser prime factor of nth product of two distinct primes.


12



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, 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, 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
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OFFSET

1,1


COMMENTS

a(n)*A070647(n) = A006881(n); a(n) < A070647(n);
a(n) = A020639(A006881(n)).


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000


MATHEMATICA

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 *)


PROG

(Haskell)
a096916 = a020639 . a006881  Reinhard Zumkeller, Sep 23 2011
(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


CROSSREFS

Cf. A084126, A195758.
Sequence in context: A107789 A124064 A317369 * A098014 A059957 A165924
Adjacent sequences: A096913 A096914 A096915 * A096917 A096918 A096919


KEYWORD

nonn,look


AUTHOR

Reinhard Zumkeller, Jul 15 2004


STATUS

approved



