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A193294
Sum of even divisors of Fibonacci(n).
2
0, 0, 2, 0, 0, 14, 0, 0, 36, 0, 0, 390, 0, 0, 744, 0, 0, 5040, 0, 0, 11816, 0, 0, 154752, 0, 0, 213840, 0, 0, 1999872, 0, 0, 3564360, 0, 0, 46656000, 0, 0, 63517896, 0, 0, 526048320, 0, 0, 1465647264, 0, 0, 16665772032, 0, 0, 20377766312, 0, 0, 173039328000
OFFSET
1,3
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..1000
EXAMPLE
a(6) = 14 because Fibonacci(6) = 8, and the sum of the even divisors {2, 4, 8} = 14.
MATHEMATICA
Table[Total[Select[Divisors[Fibonacci[n]], EvenQ[ # ]&]], {n, 75}]
PROG
(PARI) a(n)=if(n%3, 0, 2*sigma(fibonacci(n)/2)) \\ Charles R Greathouse IV, Jul 31 2011
CROSSREFS
Sequence in context: A350732 A231031 A061848 * A231049 A231080 A231246
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jul 21 2011
STATUS
approved