The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 16 |
| 3 | 1296 |
| 4 | 23040 |
| 5 | 810000 |
| 6 | 7257600 |
| 7 | 16934400 |
| 8 | 283852800 |
| 9 | 1437004800 |
| 10 | 1944810000 |
| 11 | 13970880000 |
| 12 | 30735936000 |
| 13 | 232475443200 |
| 14 | 852409958400 |
| 15 | 1765360396800 |
| 16 | 3269185920000 |
| 17 | 7192209024000 |
| 18 | 8029628006400 |
| 19 | 28473963210000 |
| 20 | 97893956160000 |
| 21 | 181803061440000 |
| 22 | 1086822696960000 |
[1,16,1296,23040,810000,7257600,16934400, 283852800,1437004800,1944810000,13970880000, 30735936000,232475443200,852409958400, 1765360396800,3269185920000,7192209024000, 8029628006400,28473963210000,97893956160000, 181803061440000,1086822696960000] |