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A139044 Smallest prime divisor of the Fibonacci numbers > 1. 5
2, 3, 5, 2, 13, 3, 2, 5, 89, 2, 233, 13, 2, 3, 1597, 2, 37, 3, 2, 89, 28657, 2, 5, 233, 2, 3, 514229, 2, 557, 3, 2, 1597, 5, 2, 73, 37, 2, 3, 2789, 2, 433494437, 3, 2, 139, 2971215073, 2, 13, 5, 2, 3, 953, 2, 5, 3, 2, 59, 353, 2, 4513, 557, 2, 3, 5, 2, 269, 3, 2, 5, 6673, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Fibonacci number > 1, divided by its largest proper divisor.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..1406 (terms 1..200 Vincenzo Librandi)

FORMULA

a(n) = A000045(n+2)/A032742(A000045(n+2)) = A000045(n+2)/A139045(n).

a(n) = A020639(A000045(n+2)). - Michel Marcus, Nov 15 2014

a(n) = A060383(n+2). - Alois P. Heinz, Oct 11 2015

MAPLE

with(numtheory): with(combinat): a:=proc(n) options operator, arrow: op(2, divisors(fibonacci(n))) end proc: seq(a(n), n=3..60); # Emeric Deutsch, May 02 2008

MATHEMATICA

First[First[FactorInteger[ # ]]]&/@Fibonacci[Range[3, 40]] (* Harvey P. Dale, Apr 30 2008 *)

PROG

(PARI) a(n) = factor(fibonacci(n+2))[1, 1]; \\ Michel Marcus, Nov 15 2014

(MAGMA) [Minimum(PrimeDivisors(Fibonacci(n+2))): n in [1..70]]; // Vincenzo Librandi, Dec 24 2016

CROSSREFS

Cf. A000045, A032742, A060383, A133021, A139045.

Sequence in context: A079369 A102867 A060383 * A060442 A060385 A080648

Adjacent sequences:  A139041 A139042 A139043 * A139045 A139046 A139047

KEYWORD

nonn

AUTHOR

Omar E. Pol, Apr 23 2008

EXTENSIONS

More terms from Emeric Deutsch and Harvey P. Dale, May 02 2008

More terms from Vincenzo Librandi, Dec 24 2016

STATUS

approved

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Last modified June 14 05:51 EDT 2021. Contains 345018 sequences. (Running on oeis4.)