n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 1 |
3 | 9 |
4 | 17 |
5 | 80 |
6 | 198 |
7 | 748 |
8 | 2107 |
9 | 7236 |
10 | 21680 |
11 | 71279 |
12 | 219879 |
13 | 708436 |
14 | 2215513 |
15 | 7071210 |
16 | 22256567 |
17 | 70723367 |
18 | 223272153 |
19 | 708017329 |
20 | 2238347440 |
21 | 7091170416 |
22 | 22433032016 |
[0,1,1,9,17,80,198,748,2107,7236,21680,71279, 219879,708436,2215513,7071210,22256567,70723367, 223272153,708017329,2238347440,7091170416, 22433032016] |