n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 4 |
4 | 13 |
5 | 36 |
6 | 132 |
7 | 584 |
8 | 2054 |
9 | 7700 |
10 | 29208 |
11 | 113024 |
12 | 428784 |
13 | 1637248 |
14 | 6322400 |
15 | 24241600 |
16 | 93878180 |
17 | 360819968 |
18 | 1402924464 |
19 | 5410402304 |
20 | 21069262688 |
21 | 81508818720 |
22 | 317854067456 |
23 | 1233012730240 |
24 | 4813042237968 |
25 | 18714480000512 |
[0,0,4,13,36,132,584,2054,7700,29208,113024, 428784,1637248,6322400,24241600,93878180, 360819968,1402924464,5410402304,21069262688, 81508818720,317854067456,1233012730240, 4813042237968,18714480000512] |