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A139044
Smallest prime divisor of the Fibonacci numbers > 1.
6
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
OFFSET
1,1
COMMENTS
Fibonacci number > 1, divided by its largest proper divisor.
LINKS
Tyler Busby, Table of n, a(n) for n = 1..1450 (terms 1..200 Vincenzo Librandi, terms 201..1406 from Amiram Eldar)
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
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