n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 2 |
3 | 6 |
4 | 28 |
5 | 220 |
6 | 2520 |
7 | 34510 |
8 | 519680 |
9 | 8527680 |
10 | 154831600 |
11 | 3151456000 |
12 | 71830281600 |
13 | 1809141934600 |
14 | 49559087177600 |
15 | 1459865188782000 |
16 | 45970426027926400 |
17 | 1543274016213529600 |
18 | 55120521154277779200 |
19 | 2088917638216953544000 |
20 | 83717918489664018560000 |
[1,1,2,6,28,220,2520,34510,519680,8527680, 154831600,3151456000,71830281600,1809141934600, 49559087177600,1459865188782000,45970426027926400, 1543274016213529600,55120521154277779200, 2088917638216953544000,83717918489664018560000] |