n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 9 |
3 | 30 |
4 | 132 |
5 | 720 |
6 | 4680 |
7 | 35280 |
8 | 302400 |
9 | 2903040 |
10 | 30844800 |
11 | 359251200 |
12 | 4550515200 |
13 | 62270208000 |
14 | 915372057600 |
15 | 14384418048000 |
16 | 240612083712000 |
17 | 4268249137152000 |
18 | 80029671321600000 |
19 | 1581386305314816000 |
20 | 32844177110384640000 |
21 | 715273190403932160000 |
22 | 16298010552775311360000 |
[1,4,9,30,132,720,4680,35280,302400,2903040, 30844800,359251200,4550515200,62270208000, 915372057600,14384418048000,240612083712000, 4268249137152000,80029671321600000, 1581386305314816000,32844177110384640000, 715273190403932160000,16298010552775311360000] |