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A197863 Smallest powerful number that is a multiple of n. 4
1, 4, 9, 4, 25, 36, 49, 8, 9, 100, 121, 36, 169, 196, 225, 16, 289, 36, 361, 100, 441, 484, 529, 72, 25, 676, 27, 196, 841, 900, 961, 32, 1089, 1156, 1225, 36, 1369, 1444, 1521, 200, 1681, 1764, 1849, 484, 225, 2116, 2209, 144, 49, 100, 2601, 676, 2809, 108, 3025 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Multiplicative with a(p^e) = p^max(e,2).

LINKS

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

MATHEMATICA

With[{pwrnos=Join[{1}, Select[Range[5000], Min[Transpose[ FactorInteger[#]] [[2]]]>1&]]}, Flatten[Table[Select[pwrnos, Divisible[#, n]&, 1], {n, 60}]]] (* Harvey P. Dale, Aug 14 2012 *)

PROG

(PARI) a(n)=local(fm=factor(n)); prod(k=1, matsize(fm)[1], fm[k, 1]^max(fm[k, 2], 2))

(Haskell)

a197863 n = product $

   zipWith (^) (a027748_row n) (map (max 2) $ a124010_row n)

-- Reinhard Zumkeller, Jan 06 2012

CROSSREFS

Cf. A087320, A001694.

Cf. A027748, A124010, A007948.

Sequence in context: A005063 A235323 A078615 * A087320 A087321 A053143

Adjacent sequences:  A197860 A197861 A197862 * A197864 A197865 A197866

KEYWORD

nonn,mult

AUTHOR

Franklin T. Adams-Watters, Oct 18 2011

STATUS

approved

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Last modified July 28 12:23 EDT 2014. Contains 244997 sequences.