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 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 17 |
| 10 | 17 |
| 11 | 49 |
| 12 | 49 |
| 13 | 253 |
| 14 | 253 |
| 15 | 4269 |
| 16 | 4269 |
| 17 | 109305 |
| 18 | 109305 |
| 19 | 2719409 |
| 20 | 2719409 |
| 21 | 106590781 |
| 22 | 106590781 |
[1,1,1,1,1,1,1,1,17,17,49,49,253,253,4269,4269, 109305,109305,2719409,2719409,106590781,106590781] |