| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 162 |
| 4 | 280 |
| 5 | 12320 |
| 6 | 524880 |
| 7 | 1106560 |
| 8 | 96342400 |
| 9 | 7142567040 |
| 10 | 17041024000 |
| 11 | 2324549427200 |
| 12 | 254561089305600 |
| 13 | 664565853952000 |
| 14 | 126757680265216000 |
| 15 | 18763697892715776000 |
| 16 | 52580450364682240000 |
| 17 | 13106744139423334400000 |
| 18 | 2480410751833883860992000 |
[1,1,10,162,280,12320,524880,1106560,96342400, 7142567040,17041024000,2324549427200, 254561089305600,664565853952000, 126757680265216000,18763697892715776000, 52580450364682240000,13106744139423334400000, 2480410751833883860992000] |