A000698 - cp's OEIS frontend

A000698 A problem of configurations: a(0) = 1; for n>0, a(n) = (2n-1)!! - Sum_{k=1..n-1} (2k-1)!! a(n-k). Also the number of shellings of an n-cube, divided by 2^n n!.

n	a(n)
0	1
1	1
2	2
3	10
4	74
5	706
6	8162
7	110410
8	1708394
9	29752066
10	576037442
11	12277827850
12	285764591114
13	7213364729026
14	196316804255522
15	5731249477826890
16	178676789473121834
17	5925085744543837186
18	208256802758892355202
19	7734158085942678174730

[1, 1, 2, 10, 74, 706, 8162, 110410, 1708394, 29752066, 576037442, 12277827850, 285764591114, 7213364729026, 196316804255522, 5731249477826890, 178676789473121834, 5925085744543837186, 208256802758892355202, 7734158085942678174730]

cp's OEIS Frontend

A000698 A problem of configurations: a(0) = 1; for n>0, a(n) = (2n-1)!! - Sum_{k=1..n-1} (2k-1)!! a(n-k). Also the number of shellings of an n-cube, divided by 2^n n!.

Table of values

List of values