The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 10 |
| 4 | 42 |
| 5 | 352 |
| 6 | 1360 |
| 7 | 11616 |
| 8 | 43680 |
| 9 | 381952 |
| 10 | 1416960 |
| 11 | 12620800 |
| 12 | 46441472 |
| 13 | 419512320 |
| 14 | 1535352832 |
| 15 | 14021353472 |
| 16 | 51117465600 |
| 17 | 470886645760 |
| 18 | 1711716106240 |
| 19 | 15879295991808 |
| 20 | 57592095965184 |
| 21 | 537381547540480 |
| 22 | 1945481074704384 |
[1,10,42,352,1360,11616,43680,381952,1416960, 12620800,46441472,419512320,1535352832, 14021353472,51117465600,470886645760, 1711716106240,15879295991808,57592095965184, 537381547540480,1945481074704384] |