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Search: id:A088387
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| A088387 |
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Prime corresponding to largest prime power factor of n, a(1)=1. |
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+0
4
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| 1, 2, 3, 2, 5, 3, 7, 2, 3, 5, 11, 2, 13, 7, 5, 2, 17, 3, 19, 5, 7, 11, 23, 2, 5, 13, 3, 7, 29, 5, 31, 2, 11, 17, 7, 3, 37, 19, 13, 2, 41, 7, 43, 11, 3, 23, 47, 2, 7, 5, 17, 13, 53, 3, 11, 2, 19, 29, 59, 5, 61, 31, 3, 2, 13, 11, 67, 17, 23, 7, 71, 3, 73, 37, 5, 19, 11, 13, 79, 2, 3, 41, 83, 7, 17
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Most significant prime factor of n: If n = (p_1^e_1)(p_2^e_2)(p_3^e_3)... and max(p_1^e_1,p_2^e_2,...) = p_k^e_k then a(n) = p_k.
a(n*a(n)) = a(n) - Sam Alexander (amnalexander(AT)yahoo.com), Dec 15 2003
A034699(n) = a(n)^A088388(n).
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EXAMPLE
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a(6) = a(2*3) = 3 because 3^1 > 2^1
a(36) = a((2^2)(3^2)) = 3 because 3^2 > 2^2
a(12) = a((2^2)*3) = 2 because 2^2 > 3^1
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MATHEMATICA
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f[n_] := Sort[ {#[[1]]^#[[2]], #[[1]]} & /@ FactorInteger@ n][[ -1, 2]]; Array[f, 85] (* Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 05 2007 *)
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CROSSREFS
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Sequence in context: A076690 A086287 A090662 this_sequence A162325 A006530 A102095
Adjacent sequences: A088384 A088385 A088386 this_sequence A088388 A088389 A088390
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KEYWORD
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easy,nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Sep 28 2003
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EXTENSIONS
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More terms from Ray Chandler (rayjchandler(AT)sbcglobal.net), Dec 20 2003
Edited by N. J. A. Sloane (njas(AT)research.att.com) at the suggestion of Stefan Steinerberger, Nov 04 2007
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