n | a(n) |
---|---|
1 | 0 |
2 | 1 |
3 | 3 |
4 | 3 |
5 | 140 |
6 | 420 |
7 | 840 |
8 | 840 |
9 | 10810800 |
10 | 75675600 |
11 | 454053600 |
12 | 2270268000 |
13 | 9081072000 |
14 | 27243216000 |
15 | 54486432000 |
16 | 54486432000 |
17 | 52401161274029568000 |
18 | 786017419110443520000 |
19 | 11004243867546209280000 |
20 | 143055170278100720640000 |
[0,1,3,3,140,420,840,840,10810800,75675600, 454053600,2270268000,9081072000,27243216000, 54486432000,54486432000,52401161274029568000, 786017419110443520000,11004243867546209280000, 143055170278100720640000] |