The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 52 |
| 5 | 504 |
| 6 | 6808 |
| 7 | 122304 |
| 8 | 2820048 |
| 9 | 81183200 |
| 10 | 2853990496 |
| 11 | 120321094656 |
| 12 | 5991955466560 |
| 13 | 347996920977664 |
| 14 | 23312947041336960 |
| 15 | 1784445116557881344 |
| 16 | 154767015393810489600 |
| 17 | 15098457734490931766784 |
[1,1,2,8,52,504,6808,122304,2820048,81183200, 2853990496,120321094656,5991955466560, 347996920977664,23312947041336960, 1784445116557881344,154767015393810489600, 15098457734490931766784] |