n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 0 |
4 | 2 |
5 | 4 |
6 | 9 |
7 | 19 |
8 | 51 |
9 | 107 |
10 | 219 |
11 | 417 |
12 | 757 |
13 | 1470 |
14 | 2666 |
15 | 5040 |
16 | 9280 |
17 | 17210 |
18 | 32039 |
19 | 59762 |
20 | 111811 |
21 | 210627 |
22 | 397968 |
[0,0,0,2,4,9,19,51,107,219,417,757,1470,2666,5040, 9280,17210,32039,59762,111811,210627,397968] |