| n | a(n) |
|---|---|
| 4 | 1248 |
| 5 | 17216 |
| 6 | 269568 |
| 7 | 4732416 |
| 8 | 92160000 |
| 9 | 1972887552 |
| 10 | 46068203520 |
| 11 | 1165619036160 |
| 12 | 31774337925120 |
| 13 | 928516276224000 |
| 14 | 28959369005629440 |
| 15 | 960261079538073600 |
| 16 | 33735701275921612800 |
| 17 | 1251834624646683033600 |
| 18 | 48927351154151522304000 |
| 19 | 2009139126253980431155200 |
| 20 | 86482397103403554570240000 |
[1248,17216,269568,4732416,92160000,1972887552, 46068203520,1165619036160,31774337925120, 928516276224000,28959369005629440, 960261079538073600,33735701275921612800, 1251834624646683033600,48927351154151522304000, 2009139126253980431155200, 86482397103403554570240000] |