A193293 Sum of odd divisors of Fibonacci(n).

1, 1, 1, 4, 6, 1, 14, 32, 18, 72, 90, 13, 234, 420, 372, 1536, 1598, 360, 4332, 12096, 5908, 18000, 28658, 2496, 93062, 122148, 106920, 473760, 514230, 142848, 1349244, 3391488, 1782180, 5708056, 11924808, 1555200, 24664200, 40504200, 31758948, 209212416

Offset

1,4

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..1000

Formula

a(n) = A000593(A000045(n)). - Michel Marcus, Jan 14 2014

Example

a(9) = 18 because Fibonacci(9) = 34 = 2*17 and the sum of the odd divisors
  {1, 17}= 18.

Mathematica

Table[Total[Select[Divisors[Fibonacci[n]], OddQ[ # ]&]], {n, 75}]

Prog

(PARI) a(n)=n=fibonacci(n); sigma(n>>valuation(n, 2)) \\ Charles R Greathouse IV, Jul 31 2011

Crossrefs

Cf. A000045, A193292.

Sequence in context: A230256 A362296 A333668 * A258220 A158391 A379778

Adjacent sequences: A193290 A193291 A193292 * A193294 A193295 A193296

Keyword

nonn

Author

Michel Lagneau, Jul 21 2011

Status

approved