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 | 9 |
| 8 | 9 |
| 9 | 33 |
| 10 | 33 |
| 11 | 89 |
| 12 | 89 |
| 13 | 853 |
| 14 | 853 |
| 15 | 34557 |
| 16 | 34557 |
| 17 | 906369 |
| 18 | 906369 |
| 19 | 18920177 |
| 20 | 18920177 |
| 21 | 1254520087 |
| 22 | 1254520087 |
| 23 | 193995577775 |
| 24 | 193995577775 |
[1,1,1,1,1,1,9,9,33,33,89,89,853,853,34557,34557, 906369,906369,18920177,18920177,1254520087, 1254520087,193995577775,193995577775] |