The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 9 |
| 7 | 29 |
| 8 | 121 |
| 9 | 541 |
| 10 | 3221 |
| 11 | 21119 |
| 12 | 159497 |
| 13 | 1485397 |
| 14 | 18836335 |
| 15 | 303422599 |
| 16 | 5770504647 |
[1,1,1,1,1,9,29,121,541,3221,21119,159497,1485397, 18836335,303422599,5770504647] |