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A086411 Greatest prime factor of 3-smooth numbers. 5
1, 2, 3, 2, 3, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) = A006530(A003586(n)).

A086410(n) <= a(n) <= 3.

a(A033845(n)) = A086410(A033845(n))+1; a(A006899(n)) = A086410(A006899(n)). [Reinhard Zumkeller, Sep 25 2008]

LINKS

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

MATHEMATICA

Reap[Do[p = FactorInteger[n][[-1, 1]]; If[p < 5, Sow[p]], {n, 1, 2*10^5}] ][[2, 1]] (* Jean-Fran├žois Alcover, Dec 17 2017 *)

CROSSREFS

Cf. A003586, A006530, A006899, A033845, A086410.

Sequence in context: A304097 A251101 A065067 * A105528 A076225 A215776

Adjacent sequences:  A086408 A086409 A086410 * A086412 A086413 A086414

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jul 18 2003

STATUS

approved

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Last modified September 16 12:41 EDT 2019. Contains 327113 sequences. (Running on oeis4.)