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A085079 Largest number with the prime signature of n using prime divisors of n. 5
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 18, 13, 14, 15, 16, 17, 18, 19, 50, 21, 22, 23, 54, 25, 26, 27, 98, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 250, 41, 42, 43, 242, 75, 46, 47, 162, 49, 50, 51, 338, 53, 54, 55, 686, 57, 58, 59, 150, 61, 62, 147, 64, 65, 66, 67, 578, 69, 70 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Though a large number of initial terms match, this sequence is different from A069799. Example: a(1500) = a(2^2*3*5^3) = 5^3*3^2*2 = 2250, whereas A069799(1500) = 5^2*3*2^3 = 600.

The first term that is different from A069799 is a(18). - Ivan Neretin, Jul 29 2015

LINKS

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

FORMULA

a(n) >= n. - Michel Marcus, Jul 30 2015

EXAMPLE

20 = 2^2*5, hence a(20) = 5^2*2 = 50.

MATHEMATICA

Table[Times @@ ((ar = Transpose[FactorInteger[n]])[[1]]^Sort[ar[[2]]]), {n, 70}] (* Ivan Neretin, Jul 29 2015*)

fise[n_]:=Module[{fi=FactorInteger[n]}, Times@@(fi[[All, 1]]^Sort[ fi[ [All, 2]]])]; Array[fise, 100] (* Harvey P. Dale, Sep 18 2017 *)

PROG

(Haskell)

import Data.List (sort)

a085079 n = product $ zipWith (^) (a027748_row n) (sort $ a124010_row n)

-- Reinhard Zumkeller, Apr 27 2013

CROSSREFS

Cf. A069799.

Cf. A027748, A124010, A089247, A071364, A046523.

Sequence in context: A225891 A295417 A293448 * A289234 A033000 A130573

Adjacent sequences:  A085076 A085077 A085078 * A085080 A085081 A085082

KEYWORD

nonn

AUTHOR

Amarnath Murthy, Jul 01 2003

EXTENSIONS

Corrected and extended by Ray Chandler, Aug 17 2003

STATUS

approved

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Last modified October 23 18:36 EDT 2018. Contains 316529 sequences. (Running on oeis4.)