The On-Line Encyclopedia of Integer Sequences (OEIS)

A096917 revision #8

A096917

Smallest prime factor of n-th product of 3 distinct primes.

2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 5, 3, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 5, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 2, 5, 2, 2, 2, 3, 2, 3, 2, 3, 2, 2, 3, 2, 3, 2, 2, 3, 5, 2, 2, 2, 3, 2, 5, 2, 3, 2, 2, 3, 2, 3, 2

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OFFSET

1,1

COMMENTS

a(n)*A096918(n)*A096919(n) = A007304(n); a(n) < A096918(n) < A096919(n);

a(n) = A020639(A007304(n)).

LINKS

Table of n, a(n) for n=1..102.

MATHEMATICA

f[n_]:=Last/@FactorInteger[n]=={1, 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, 7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Apr 10 2010 *)

CROSSREFS

Sequence in context: A258757 A351399 A024708 * A336664 A335108 A359238

Adjacent sequences: A096914 A096915 A096916 * A096918 A096919 A096920

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 15 2004

STATUS

approved