The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 3 |
| 5 | 15 |
| 6 | 15 |
| 7 | 315 |
| 8 | 105 |
| 9 | 567 |
| 10 | 405 |
| 11 | 155925 |
| 12 | 467775 |
| 13 | 1216215 |
| 14 | 34749 |
| 15 | 638512875 |
| 16 | 638512875 |
| 17 | 2170943775 |
| 18 | 32564156625 |
| 19 | 1856156927625 |
| 20 | 3093594879375 |
| 21 | 38979295480125 |
| 22 | 5568470782875 |
| 23 | 49308808782358125 |
| 24 | 2900518163668125 |
| 25 | 284473896821296875 |
| 26 | 1232720219558953125 |
[1,1,3,3,15,15,315,105,567,405,155925,467775, 1216215,34749,638512875,638512875,2170943775, 32564156625,1856156927625,3093594879375, 38979295480125,5568470782875,49308808782358125, 2900518163668125,284473896821296875, 1232720219558953125] |