A000261 - cp's OEIS frontend

A000261 a(n) = na(n-1) + (n-3)a(n-2), with a(1) = 0, a(2) = 1.

n	a(n)
1	0
2	1
3	3
4	13
5	71
6	465
7	3539
8	30637
9	296967
10	3184129
11	37401155
12	477471021
13	6581134823
14	97388068753
15	1539794649171
16	25902759280525
17	461904032857319
18	8702813980639617
19	172743930157869827
20	3602826440828270029
21	78768746000235327495
22	1801366114380914335441

[0, 1, 3, 13, 71, 465, 3539, 30637, 296967, 3184129, 37401155, 477471021, 6581134823, 97388068753, 1539794649171, 25902759280525, 461904032857319, 8702813980639617, 172743930157869827, 3602826440828270029, 78768746000235327495, 1801366114380914335441]

cp's OEIS Frontend

A000261 a(n) = na(n-1) + (n-3)a(n-2), with a(1) = 0, a(2) = 1.

Table of values

List of values

cp's OEIS Frontend

A000261 a(n) = n*a(n-1) + (n-3)*a(n-2), with a(1) = 0, a(2) = 1.

Table of values

List of values

A000261 a(n) = na(n-1) + (n-3)a(n-2), with a(1) = 0, a(2) = 1.