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 | 5 |
| 8 | 5 |
| 9 | 19 |
| 10 | 19 |
| 11 | 97 |
| 12 | 97 |
| 13 | 863 |
| 14 | 863 |
| 15 | 18767 |
| 16 | 18767 |
| 17 | 490889 |
| 18 | 490889 |
| 19 | 19713443 |
| 20 | 19713443 |
| 21 | 1413873475 |
| 22 | 1413873475 |
| 23 | 167866752937 |
| 24 | 167866752937 |
| 25 | 30662833126025 |
| 26 | 30662833126025 |
[1,1,1,1,1,1,5,5,19,19,97,97,863,863,18767,18767, 490889,490889,19713443,19713443,1413873475, 1413873475,167866752937,167866752937, 30662833126025,30662833126025] |