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A085079
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Largest number with the prime signature of n using prime divisors of n.
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6
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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
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OFFSET
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1,2
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COMMENTS
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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
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LINKS
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Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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FORMULA
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a(n) >= n. - Michel Marcus, Jul 30 2015
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EXAMPLE
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20 = 2^2*5, hence a(20) = 5^2*2 = 50.
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MATHEMATICA
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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 *)
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PROG
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(Haskell)
import Data.List (sort)
a085079 n = product $ zipWith (^) (a027748_row n) (sort $ a124010_row n)
-- Reinhard Zumkeller, Apr 27 2013
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CROSSREFS
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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
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy, Jul 01 2003
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EXTENSIONS
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Corrected and extended by Ray Chandler, Aug 17 2003
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STATUS
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approved
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