The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 13 |
| 3 | 289 |
| 4 | 13814 |
| 5 | 1795898 |
| 6 | 265709592 |
| 7 | 70163924440 |
| 8 | 20610999526800 |
| 9 | 9097511018219760 |
| 10 | 6845834489829830144 |
[1,2,13,289,13814,1795898,265709592,70163924440, 20610999526800,9097511018219760, 6845834489829830144] |