n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 1 |
4 | 6 |
5 | 30 |
6 | 140 |
7 | 663 |
8 | 3186 |
9 | 15642 |
10 | 78441 |
11 | 400842 |
12 | 2084698 |
13 | 11009358 |
14 | 58955139 |
15 | 319619706 |
16 | 1752122667 |
17 | 9700923252 |
18 | 54194387085 |
19 | 305216395077 |
20 | 1731579241287 |
21 | 9889280682948 |
22 | 56822058078669 |
23 | 328300135291659 |
24 | 1906449141877331 |
25 | 11122447670117451 |
26 | 65168427936552522 |
[0,0,1,6,30,140,663,3186,15642,78441,400842, 2084698,11009358,58955139,319619706,1752122667, 9700923252,54194387085,305216395077,1731579241287, 9889280682948,56822058078669,328300135291659, 1906449141877331,11122447670117451, 65168427936552522] |