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A088387 Prime corresponding to largest prime power factor of n, a(1)=1. 3
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; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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).

LINKS

Table of n, a(n) for n=1..85.

EXAMPLE

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

MATHEMATICA

f[n_] := Sort[ {#[[1]]^#[[2]], #[[1]]} & /@ FactorInteger@ n][[ -1, 2]]; Array[f, 85] (* Robert G. Wilson v, Nov 05 2007 *)

CROSSREFS

Sequence in context: A076690 A086287 A090662 * A197861 A180506 A162325

Adjacent sequences:  A088384 A088385 A088386 * A088388 A088389 A088390

KEYWORD

easy,nonn

AUTHOR

Reinhard Zumkeller, Sep 28 2003

EXTENSIONS

More terms from Ray Chandler, Dec 20 2003

Edited by N. J. A. Sloane at the suggestion of Stefan Steinerberger, Nov 04 2007

STATUS

approved

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Last modified May 21 11:29 EDT 2013. Contains 225478 sequences.