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A193291
Number of even divisors of Fibonacci(n).
3
0, 0, 1, 0, 0, 3, 0, 0, 2, 0, 0, 12, 0, 0, 4, 0, 0, 12, 0, 0, 4, 0, 0, 60, 0, 0, 8, 0, 0, 48, 0, 0, 4, 0, 0, 128, 0, 0, 4, 0, 0, 48, 0, 0, 16, 0, 0, 288, 0, 0, 4, 0, 0, 96, 0, 0, 16, 0, 0, 768, 0, 0, 16, 0, 0, 48, 0, 0, 16, 0, 0, 1280, 0, 0, 24, 0, 0, 96, 0
OFFSET
1,6
LINKS
FORMULA
a(n) = A183063(A000045(n)). - Amiram Eldar, Sep 03 2019
EXAMPLE
a(6) = 3 because Fibonacci(6) = 8 and the 3 even divisors are {2, 4, 8}.
MATHEMATICA
a[n_] := Block[{d = Divisors[Fibonacci[n]]}, Count[EvenQ[d], True]]; Table[a[n], {n, 110}]
PROG
(PARI) a(n)=if(n%3, 0, numdiv(fibonacci(n)/2)) \\ Charles R Greathouse IV, Jul 30 2011
CROSSREFS
Sequence in context: A344118 A212221 A343088 * A096936 A115979 A067168
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jul 21 2011
STATUS
approved