A195209 Sum of even divisors of !n.

0, 0, 0, 2, 0, 72, 0, 2704, 0, 268128, 0, 17621496, 0, 4974281208, 0, 549790303712, 0, 245357774621280, 0, 67684833350266496, 0, 36434223374991414336, 0, 10781900341537812480000, 0, 14585451990785851336761600, 0, 4706112122106541811177554944, 0, 5607912482098966721098538956800, 0

Offset: 0

Author

Michel Lagneau, Sep 13 2011

Keywords

• nonn

Examples

			a(7) = 2704 because the divisors of  !7 = 1854 are  {1, 2, 3, 6, 9, 18, 103, 206, 309, 618, 927, 1854}, and the sum of the 6  even divisors  2, 6, 18, 206, 618 and 1854 is 2704.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 0..82

Crossrefs

Cf. A000166, A146076, A195207, A195208, A195210.

Programs

Mathematica

Table[Total[Select[Divisors[Subfactorial[n]], EvenQ[ # ]&]], {n, 0, 25}]

Formula

From Amiram Eldar, Aug 02 2024: (Start)

a(n) = A146076(A000166(n)), for n != 1.

a(2*n) = 0. (End)

Extensions

a(26)-a(30) from Amiram Eldar, Aug 02 2024