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
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jul 21 2011
STATUS
approved