n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 3 |
3 | 12 |
4 | 66 |
5 | 450 |
6 | 3690 |
7 | 35280 |
8 | 385560 |
9 | 4740120 |
10 | 64751400 |
11 | 972972000 |
12 | 15949256400 |
13 | 283232149200 |
14 | 5416632421200 |
15 | 110988861984000 |
16 | 2425817682288000 |
17 | 56333385828720000 |
18 | 1385151050307024000 |
19 | 35950878932544576000 |
20 | 982196278209226080000 |
21 | 28175806418228108640000 |
[1,1,3,12,66,450,3690,35280,385560,4740120, 64751400,972972000,15949256400,283232149200, 5416632421200,110988861984000,2425817682288000, 56333385828720000,1385151050307024000, 35950878932544576000,982196278209226080000, 28175806418228108640000] |