A356600 - cp's OEIS frontend

A356600 a(n) = n! * Sum_{k=1..n} sigma_2(k)/(k * (n-k)!).

n	a(n)
1	1
2	7
3	38
4	240
5	1509
6	12115
7	96326
8	929432
9	9421089
10	108909943
11	1249105054
12	17862483320
13	241674418101
14	3676733397363
15	59149265744302
16	1058605924855568
17	18041587282787489
18	363409114370324295
19	6970858463185187062
20	153017341796727034336
21	3360005220780469981157

[1, 7, 38, 240, 1509, 12115, 96326, 929432, 9421089, 108909943, 1249105054, 17862483320, 241674418101, 3676733397363, 59149265744302, 1058605924855568, 18041587282787489, 363409114370324295, 6970858463185187062, 153017341796727034336, 3360005220780469981157]

cp's OEIS Frontend

A356600 a(n) = n! * Sum_{k=1..n} sigma_2(k)/(k * (n-k)!).

Table of values

List of values