n | a(n) |
---|---|
0 | 0 |
1 | 2 |
2 | 20 |
3 | 126 |
4 | 648 |
5 | 2970 |
6 | 12636 |
7 | 51030 |
8 | 198288 |
9 | 747954 |
10 | 2755620 |
11 | 9959598 |
12 | 35429400 |
13 | 124357194 |
14 | 431530092 |
15 | 1482720390 |
16 | 5050815264 |
17 | 17075199330 |
18 | 57338232372 |
19 | 191385721566 |
20 | 635369601960 |
21 | 2099044209402 |
22 | 6903833113980 |
[0,2,20,126,648,2970,12636,51030,198288,747954, 2755620,9959598,35429400,124357194,431530092, 1482720390,5050815264,17075199330,57338232372, 191385721566,635369601960,2099044209402, 6903833113980] |