|
| |
|
|
A096916
|
|
Lesser prime factor of n-th product of two distinct primes.
|
|
13
|
|
|
|
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
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
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: A124064 A348470 A317369 * A098014 A059957 A165924
Adjacent sequences: A096913 A096914 A096915 * A096917 A096918 A096919
|
|
|
KEYWORD
|
nonn,look
|
|
|
AUTHOR
|
Reinhard Zumkeller, Jul 15 2004
|
|
|
STATUS
|
approved
|
| |
|
|
