OFFSET
1,3
COMMENTS
In other words, the squarefree part of the n-th Fibonacci number.
a(gcd(m,n)) = gcd(a(m),a(n)). - Robert Israel, Nov 10 2023
LINKS
Robert Israel, Table of n, a(n) for n = 1..350
EXAMPLE
a(12) = 6 since F(12) = 144 = 2^4 * 3^2 and 2 * 3 = 6.
MAPLE
f:= n -> convert(numtheory:-factorset(combinat:-fibonacci(n)), `*`):
map(f, [$1..100]); # Robert Israel, Nov 10 2023
MATHEMATICA
Table[Times@@Part[Flatten[FactorInteger[Fibonacci[n]]], 1 ;; -2 ;; 2], {n, 3, 50}] (* Alonso del Arte, Mar 02 2014 *)
PROG
(PARI) a(n) = my(f = factor(fibonacci(n))); prod(i=1, #f~, f[i, 1]); \\ Michel Marcus, Mar 02 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Carmine Suriano, Mar 02 2014
STATUS
approved