n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 1 |
4 | 12 |
5 | 36 |
6 | 114 |
7 | 375 |
8 | 1071 |
9 | 2939 |
10 | 7706 |
11 | 20417 |
12 | 53332 |
13 | 139597 |
14 | 364217 |
15 | 957111 |
16 | 2526795 |
17 | 6725234 |
18 | 18069359 |
19 | 48961462 |
[0,0,1,12,36,114,375,1071,2939,7706,20417,53332, 139597,364217,957111,2526795,6725234,18069359, 48961462] |