The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 42 |
| 5 | 438 |
| 6 | 8241 |
| 7 | 279663 |
| 8 | 17574795 |
| 9 | 2023191364 |
| 10 | 425872679440 |
| 11 | 164093026377725 |
| 12 | 115549694765467808 |
| 13 | 148496731427890025827 |
[1,2,8,42,438,8241,279663,17574795,2023191364, 425872679440,164093026377725,115549694765467808, 148496731427890025827] |