A354506 - cp's OEIS frontend

A354506 a(n) = n! * Sum_{k=1..n} ( Sum_{d|k} (-1)^(k/d+1) )/(k * (n-k)!).

n	a(n)
1	1
2	2
3	7
4	14
5	63
6	284
7	2385
8	3940
9	87717
10	940126
11	12743267
12	30055618
13	562302323
14	9005878920
15	423435780989
16	2080544097000
17	24457758561001
18	444510436079706
19	17533073308723423
20	46973556239255702
21	7501223613055891783
22	178483805340054632084
23	4396051786608296882889
24	-31788150263554644516724

[1, 2, 7, 14, 63, 284, 2385, 3940, 87717, 940126, 12743267, 30055618, 562302323, 9005878920, 423435780989, 2080544097000, 24457758561001, 444510436079706, 17533073308723423, 46973556239255702, 7501223613055891783, 178483805340054632084, 4396051786608296882889, -31788150263554644516724]

cp's OEIS Frontend

A354506 a(n) = n! * Sum_{k=1..n} ( Sum_{d|k} (-1)^(k/d+1) )/(k * (n-k)!).

Table of values

List of values