The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 52 |
| 4 | 499 |
| 5 | 6054 |
| 6 | 90227 |
| 7 | 1613754 |
| 8 | 33885079 |
| 9 | 821284774 |
| 10 | 22663681441 |
| 11 | 703996716588 |
| 12 | 24381215997619 |
[1,7,52,499,6054,90227,1613754,33885079,821284774, 22663681441,703996716588,24381215997619] |