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A115022 a(n) = F(n-th squarefree)/product{p=primes,p|(n-th squarefree)} F(p), where F(m) is m-th Fibonacci number. 1
1, 1, 1, 1, 4, 1, 11, 1, 1, 29, 61, 1, 1, 421, 199, 1, 521, 1, 83204, 1, 19801, 3571, 141961, 1, 9349, 135721, 1, 10304396, 1, 64079, 1, 6376021, 1, 313671601, 43701901, 1149851, 1, 1, 3010349, 14736206161, 156055561996, 1, 2053059121 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Robert Israel, Table of n, a(n) for n = 1..2938

EXAMPLE

The 7th squarefree integer is 10 = 2*5. So a(7) = F(10)/(F(2)F(5)) = 55/(1*5) = 11.

MAPLE

count:= 0:

for n from 1 while count < 50 do

  if numtheory:-issqrfree(n) then

     count:= count+1;

     A[count]:= combinat:-fibonacci(n)/mul(combinat:-fibonacci(p), p=numtheory:-factorset(n))

  fi

od:

seq(A[i], i=1..50); # Robert Israel, Dec 04 2018

MATHEMATICA

f[n_] := Fibonacci[n]/Times @@ (Fibonacci /@ FactorInteger[n][[;; , 1]]); f /@

Select[Range[70], SquareFreeQ[#] &] (* Amiram Eldar, Dec 04 2018 *)

CROSSREFS

Cf. A075731.

a(n)=1 if n is in A071403.

Sequence in context: A283433 A121463 A244608 * A230534 A177822 A091156

Adjacent sequences:  A115019 A115020 A115021 * A115023 A115024 A115025

KEYWORD

nonn,look

AUTHOR

Leroy Quet, Feb 28 2006

EXTENSIONS

More terms from Joshua Zucker, Jul 18 2007

STATUS

approved

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Last modified June 24 13:17 EDT 2019. Contains 324325 sequences. (Running on oeis4.)