The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 9 |
| 3 | 25 |
| 4 | 217 |
| 5 | 921 |
| 6 | 7761 |
| 7 | 41889 |
| 8 | 345465 |
| 9 | 2162617 |
| 10 | 17605249 |
| 11 | 121120209 |
| 12 | 980612161 |
| 13 | 7174425025 |
| 14 | 58079091513 |
| 15 | 442755733065 |
| 16 | 3595708057785 |
| 17 | 28197440412345 |
| 18 | 230133477721665 |
| 19 | 1841288167473105 |
| 20 | 15113407062476817 |
| 21 | 122714906949538257 |
| 22 | 1013127345082389513 |
[1,1,9,25,217,921,7761,41889,345465,2162617, 17605249,121120209,980612161,7174425025, 58079091513,442755733065,3595708057785, 28197440412345,230133477721665,1841288167473105, 15113407062476817,122714906949538257, 1013127345082389513] |