n | a(n) |
---|---|
3 | 0 |
4 | 0 |
5 | 1 |
6 | 1 |
7 | 5 |
8 | 16 |
9 | 66 |
10 | 266 |
11 | 1235 |
12 | 6350 |
13 | 37364 |
14 | 251106 |
15 | 1942085 |
16 | 17287710 |
17 | 177086792 |
18 | 2084120446 |
19 | 28125888087 |
20 | 434318629496 |
21 | 7657513894860 |
[0,0,1,1,5,16,66,266,1235,6350,37364,251106, 1942085,17287710,177086792,2084120446,28125888087, 434318629496,7657513894860] |