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A112763 Smallest prime factor of the n-th 5-smooth number. 4
1, 2, 3, 2, 5, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 5, 3, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 5, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 5, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = A020639(A051037(n));

a(n) <= A112764(n) <= 5.

a(A188427(n)) = 5 for n > 1. - David A. Corneth, Feb 07 2020

MATHEMATICA

FactorInteger[#][[1, 1]] & /@ Select[Range[3000], Last @ Map[First, FactorInteger[#]] <= 5 &] (* Amiram Eldar, Feb 07 2020 *)

PROG

(MAGMA) [1] cat [Min(PrimeDivisors(k)): k in [2..1500]| PrimeDivisors(k) subset [2, 3, 5]]; // Marius A. Burtea, Feb 07 2020

CROSSREFS

Cf. A020639, A051037, A086410, A112755, A112764, A188425, A188426, A188427.

Sequence in context: A127705 A124386 A098668 * A093476 A262597 A217607

Adjacent sequences:  A112760 A112761 A112762 * A112764 A112765 A112766

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Sep 18 2005

STATUS

approved

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Last modified May 11 06:28 EDT 2021. Contains 343784 sequences. (Running on oeis4.)