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

Author

Michel Lagneau, Jul 21 2011

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Cf. A000045, A193292.

Programs

Mathematica

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

PARI

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

Formula

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