A087906 - cp's OEIS frontend

A087906 a(n) = Sum_{d|n} (n-1)!/(d-1)!.

n	a(n)
1	1
2	2
3	3
4	13
5	25
6	301
7	721
8	10921
9	60481
10	740881
11	3628801
12	106777441
13	479001601
14	12462690241
15	134399865601
16	2833553923201
17	20922789888001
18	892191453753601
19	6402373705728001
20	268633265290790401
21	3652732042831872001
22	102181898422712908801
23	1124000727777607680001

[1, 2, 3, 13, 25, 301, 721, 10921, 60481, 740881, 3628801, 106777441, 479001601, 12462690241, 134399865601, 2833553923201, 20922789888001, 892191453753601, 6402373705728001, 268633265290790401, 3652732042831872001, 102181898422712908801, 1124000727777607680001]

cp's OEIS Frontend

A087906 a(n) = Sum_{d|n} (n-1)!/(d-1)!.

Table of values

List of values