A213720 - cp's OEIS frontend

A213720 a(0)=0, a(1)=0; for n>1, a(n) = a(n-1) + (n+2)*a(n-2) + 1.

n	a(n)
0	0
1	0
2	1
3	2
4	9
5	24
6	97
7	314
8	1285
9	4740
10	20161
11	81782
12	364037
13	1590768
14	7415361
15	34458418
16	167934917
17	822644860
18	4181343201
19	21456885262
20	113446435685
21	606954796712
22	3329669253153
23	18503539170954
24	105074939752933
25	604670497368692
26	3546768810450817
27	21082213234142886

[0, 0, 1, 2, 9, 24, 97, 314, 1285, 4740, 20161, 81782, 364037, 1590768, 7415361, 34458418, 167934917, 822644860, 4181343201, 21456885262, 113446435685, 606954796712, 3329669253153, 18503539170954, 105074939752933, 604670497368692, 3546768810450817, 21082213234142886]

cp's OEIS Frontend

A213720 a(0)=0, a(1)=0; for n>1, a(n) = a(n-1) + (n+2)*a(n-2) + 1.

Table of values

List of values