The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 2 |
| 3 | 10 |
| 4 | 104 |
| 5 | 420 |
| 6 | 3786 |
| 7 | 14826 |
| 8 | 131264 |
| 9 | 510576 |
| 10 | 4508580 |
| 11 | 17523506 |
| 12 | 154773696 |
| 13 | 602175444 |
| 14 | 5323519838 |
| 15 | 20744201142 |
| 16 | 183586707648 |
| 17 | 716553432640 |
| 18 | 6348284151024 |
| 19 | 24816637181076 |
| 20 | 220081449149440 |
| 21 | 861581808936200 |
| 22 | 7647723960962932 |
| 23 | 29978812970646870 |
| 24 | 266322435212031984 |
[2,10,104,420,3786,14826,131264,510576,4508580, 17523506,154773696,602175444,5323519838, 20744201142,183586707648,716553432640, 6348284151024,24816637181076,220081449149440, 861581808936200,7647723960962932, 29978812970646870,266322435212031984] |