n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 1 |
4 | 4 |
5 | 15 |
6 | 50 |
7 | 160 |
8 | 502 |
9 | 1545 |
10 | 4730 |
11 | 14356 |
12 | 43474 |
13 | 131145 |
14 | 395150 |
15 | 1188580 |
16 | 3572902 |
17 | 10732065 |
18 | 32225810 |
19 | 96733636 |
20 | 290322394 |
21 | 871200825 |
22 | 2614097750 |
23 | 7843255300 |
24 | 23531775502 |
25 | 70599259185 |
26 | 211805902490 |
[0,0,1,4,15,50,160,502,1545,4730,14356,43474, 131145,395150,1188580,3572902,10732065,32225810, 96733636,290322394,871200825,2614097750, 7843255300,23531775502,70599259185,211805902490] |