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A069104 Numbers n such that n divides Fibonacci(n+1). 7
1, 2, 3, 7, 13, 17, 23, 37, 43, 47, 53, 67, 73, 83, 97, 103, 107, 113, 127, 137, 157, 163, 167, 173, 193, 197, 223, 227, 233, 257, 263, 277, 283, 293, 307, 313, 317, 323, 337, 347, 353, 367, 373, 377, 383, 397, 433, 443, 457, 463, 467, 487, 503, 523, 547, 557 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Equals A003631 union A069107.

Let u(1)=u(2)=1 and (n+2)*u(n+2) = (n+1)*u(n+1) + n*u(n); then sequence gives values of k such that u(k) is an integer.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[6! ], IntegerQ[Fibonacci[ #+1]/# ]&] (* Vladimir Joseph Stephan Orlovsky, Apr 03 2009 *)

PROG

(Haskell)

import Data.List (elemIndices)

a069104 n = a069104_list !! (n-1)

a069104_list =

   map (+ 1) $ elemIndices 0 $ zipWith mod (drop 2 a000045_list) [1..]

-- Reinhard Zumkeller, Oct 13 2011

(PARI) is(n)=((Mod([1, 1; 1, 0], n))^n)[1, 1]==0 \\ Charles R Greathouse IV, Feb 03 2014

CROSSREFS

Cf. A000045, A023172, A123976, A159051.

Sequence in context: A045329 A271666 A106306 * A003631 A175443 A032449

Adjacent sequences:  A069101 A069102 A069103 * A069105 A069106 A069107

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Apr 06 2002

STATUS

approved

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Last modified September 23 03:22 EDT 2020. Contains 337291 sequences. (Running on oeis4.)