The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 105 |
| 5 | 945 |
| 6 | 1155 |
| 7 | 15015 |
| 8 | 225225 |
| 9 | 3828825 |
| 10 | 2909907 |
| 11 | 61108047 |
| 12 | 156165009 |
| 13 | 3904125225 |
| 14 | 2151252675 |
| 15 | 62386327575 |
| 16 | 1933976154825 |
| 17 | 63821213109225 |
| 18 | 27577067392875 |
| 19 | 1020351493536375 |
| 20 | 1591748329916745 |
| 21 | 65261681526586545 |
| 22 | 23192167815233235 |
| 23 | 1043647551685495575 |
[1,1,3,15,105,945,1155,15015,225225,3828825, 2909907,61108047,156165009,3904125225,2151252675, 62386327575,1933976154825,63821213109225, 27577067392875,1020351493536375,1591748329916745, 65261681526586545,23192167815233235, 1043647551685495575] |