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A009191 GCD(n, d(n)). 13
1, 2, 1, 1, 1, 2, 1, 4, 3, 2, 1, 6, 1, 2, 1, 1, 1, 6, 1, 2, 1, 2, 1, 8, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 9, 1, 2, 1, 8, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 8, 1, 2, 1, 12, 1, 2, 3, 1, 1, 2, 1, 2, 1, 2, 1, 12, 1, 2, 3, 2, 1, 2, 1, 10, 1, 2, 1, 12, 1, 2, 1, 8, 1, 6, 1, 2, 1, 2, 1, 12, 1, 2, 3, 1, 1, 2, 1, 8, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(A046642(n)) = 1.

First occurrence of k: 1, 2, 9, 8, 400, 12, 3136, 24, 36, 80, 123904, 60, 692224, 448, 2025, 384, .... Conjecture: each k is present. Robert G. Wilson v, Mar 27 2013

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

MATHEMATICA

f[n_] := GCD[n, DivisorSigma[0, n]]; Array[f, 105] (* Robert G. Wilson v, Mar 27 2013 *)

PROG

(Haskell)

a009191 n = gcd n $ a000005 n

-- Reinhard Zumkeller, May 09 2013, Aug 14 2011

(PARI) a(n)=gcd(numdiv(n), n) \\ Charles R Greathouse IV, Mar 26 2013

CROSSREFS

Sequence in context: A051119 A159269 A186728 * A229969 A260909 A114717

Adjacent sequences:  A009188 A009189 A009190 * A009192 A009193 A009194

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified September 22 17:05 EDT 2018. Contains 315270 sequences. (Running on oeis4.)