A193294 Sum of even divisors of Fibonacci(n).

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

Cf. A000045, A193291.

Sequence in context: A350732 A231031 A061848 * A231049 A231080 A231246

Adjacent sequences: A193291 A193292 A193293 * A193295 A193296 A193297

Keyword

nonn

Author

Michel Lagneau, Jul 21 2011

Status

approved