A338810 - cp's OEIS frontend

A338810 a(n) = (n!/2) * Sum_{k=1..n-1} d(k)d(n-k)/(k(n-k)), where d(n) is the number of divisors of n.

n	a(n)
1	0
2	1
3	6
4	28
5	170
6	988
7	7896
8	60492
9	555264
10	5819904
11	61776000
12	725950080
13	9894493440
14	137963243520
15	1875645434880
16	33258387456000
17	528975488563200
18	9760969019289600
19	175565885864140800
20	3608256006957772800
21	72367669059194880000
22	1745463407406243840000

[0, 1, 6, 28, 170, 988, 7896, 60492, 555264, 5819904, 61776000, 725950080, 9894493440, 137963243520, 1875645434880, 33258387456000, 528975488563200, 9760969019289600, 175565885864140800, 3608256006957772800, 72367669059194880000, 1745463407406243840000]

cp's OEIS Frontend

A338810 a(n) = (n!/2) * Sum_{k=1..n-1} d(k)d(n-k)/(k(n-k)), where d(n) is the number of divisors of n.

Table of values

List of values

cp's OEIS Frontend

A338810 a(n) = (n!/2) * Sum_{k=1..n-1} d(k)*d(n-k)/(k*(n-k)), where d(n) is the number of divisors of n.

Table of values

List of values

A338810 a(n) = (n!/2) * Sum_{k=1..n-1} d(k)d(n-k)/(k(n-k)), where d(n) is the number of divisors of n.