n | a(n) |
---|---|
0 | 1 |
1 | 2 |
2 | 9 |
3 | 40 |
4 | 190 |
5 | 924 |
6 | 4578 |
7 | 22968 |
8 | 116325 |
9 | 593450 |
10 | 3045185 |
11 | 15699840 |
12 | 81260816 |
13 | 421993040 |
14 | 2197653240 |
15 | 11472991008 |
16 | 60023749566 |
17 | 314621200260 |
18 | 1651883008050 |
19 | 8685998428800 |
20 | 45734484854520 |
21 | 241098942106440 |
22 | 1272406536645660 |
[1,2,9,40,190,924,4578,22968,116325,593450, 3045185,15699840,81260816,421993040,2197653240, 11472991008,60023749566,314621200260, 1651883008050,8685998428800,45734484854520, 241098942106440,1272406536645660] |