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A087713 Greatest prime factor of the product of the neighbors of the n-th prime. 1
3, 2, 3, 3, 5, 7, 3, 5, 11, 7, 5, 19, 7, 11, 23, 13, 29, 31, 17, 7, 37, 13, 41, 11, 7, 17, 17, 53, 11, 19, 7, 13, 23, 23, 37, 19, 79, 41, 83, 43, 89, 13, 19, 97, 11, 11, 53, 37, 113, 23, 29, 17, 11, 7, 43, 131, 67, 17, 139, 47, 71, 73, 17, 31, 157, 79, 83, 13, 173, 29, 59 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) = A006530((A000040(n)-1)*(A000040(n)+1)) = A006530(A006093(n)*A008864(n)) = A006530(A084920(n)).

Apparently a(n) = A024710(n) for n>4. - Georg Fischer, Oct 06 2018

LINKS

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

EXAMPLE

a(10) = A006530(A000040(10)^2 - 1) = A006530(29*29-1) =

A006530(840) = A006530(7*5*3*2^3) = 7.

MATHEMATICA

FactorInteger[#][[-1, 1]]&/@((#-1)(#+1)&/@Prime[Range[80]]) (* Harvey P. Dale, Oct 26 2019 *)

PROG

(Haskell)

a087713 = a006530 . a084920  -- Reinhard Zumkeller, Aug 27 2013

CROSSREFS

Sequence in context: A125748 A058680 A070544 * A089319 A140396 A117231

Adjacent sequences:  A087710 A087711 A087712 * A087714 A087715 A087716

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Sep 28 2003

EXTENSIONS

Definition clarified by Harvey P. Dale, Oct 26 2019

STATUS

approved

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Last modified April 16 17:01 EDT 2021. Contains 343050 sequences. (Running on oeis4.)