n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 3 |
3 | 3 |
4 | 15 |
5 | 33 |
6 | 105 |
7 | 297 |
8 | 879 |
9 | 2631 |
10 | 7833 |
11 | 23697 |
12 | 71385 |
13 | 216765 |
14 | 657849 |
15 | 2003151 |
16 | 6103743 |
17 | 18624693 |
18 | 56870385 |
19 | 173760513 |
20 | 531128349 |
21 | 1623881889 |
22 | 4965695331 |
23 | 15185222199 |
24 | 46435889601 |
25 | 141985777503 |
[1,0,3,3,15,33,105,297,879,2631,7833,23697,71385, 216765,657849,2003151,6103743,18624693,56870385, 173760513,531128349,1623881889,4965695331, 15185222199,46435889601,141985777503] |