| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 72 |
| 3 | 1296 |
| 4 | 31104 |
| 5 | 933120 |
| 6 | 33592320 |
| 7 | 1410877440 |
| 8 | 67722117120 |
| 9 | 3656994324480 |
| 10 | 219419659468800 |
| 11 | 14481697524940800 |
| 12 | 1042682221795737600 |
| 13 | 81329213300067532800 |
| 14 | 6831653917205672755200 |
| 15 | 614848852548510547968000 |
[1,6,72,1296,31104,933120,33592320,1410877440, 67722117120,3656994324480,219419659468800, 14481697524940800,1042682221795737600, 81329213300067532800,6831653917205672755200, 614848852548510547968000] |