A051348 - OEIS

A051348

a(n) = F(n) / Product_{p|n} F(p), where F(k) is k-th Fibonacci number and the p's in product are the distinct primes dividing n.

1, 1, 1, 3, 1, 4, 1, 21, 17, 11, 1, 72, 1, 29, 61, 987, 1, 1292, 1, 1353, 421, 199, 1, 23184, 15005, 521, 98209, 24447, 1, 83204, 1, 2178309, 19801, 3571, 141961, 7465176, 1, 9349, 135721, 20466831, 1, 10304396, 1, 7880997, 113490317, 64079, 1

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OFFSET

1,4

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = 1 if n is prime. - Joerg Arndt, Sep 07 2021

EXAMPLE

a(15) = F(15) / (F(3) * F(5)) = 610 / (2*5) = 61.

MATHEMATICA

fib[n_]:=Fibonacci[n]/Times@@(Fibonacci[#]&/@Transpose[ FactorInteger[ n]][[1]]); Array[fib, 50] (* Harvey P. Dale, May 19 2012 *)

CROSSREFS

Cf. A000045.

Sequence in context: A321743 A341766 A131632 * A253828 A190445 A141648

Adjacent sequences: A051345 A051346 A051347 * A051349 A051350 A051351

KEYWORD

nonn

AUTHOR

Leroy Quet

STATUS

approved