A220699 - cp's OEIS frontend

A220699 a(0)=0, a(1)=0; for n>1, a(n) = a(n-1) + (n-4)*a(n-2) + 1.

n	a(n)
0	0
1	0
2	1
3	2
4	3
5	6
6	13
7	32
8	85
9	246
10	757
11	2480
12	8537
13	30858
14	116229
15	455668
16	1850417
17	7774102
18	33679941
19	150291472
20	689170529
21	3244125554
22	15649195077
23	77287580604
24	390271482145
25	2013310674830
26	10599283282021

[0, 0, 1, 2, 3, 6, 13, 32, 85, 246, 757, 2480, 8537, 30858, 116229, 455668, 1850417, 7774102, 33679941, 150291472, 689170529, 3244125554, 15649195077, 77287580604, 390271482145, 2013310674830, 10599283282021]

cp's OEIS Frontend

A220699 a(0)=0, a(1)=0; for n>1, a(n) = a(n-1) + (n-4)*a(n-2) + 1.

Table of values

List of values