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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 48 |
| 5 | 480 |
| 6 | 5760 |
| 7 | 92160 |
| 8 | 1658880 |
| 9 | 36495360 |
| 10 | 1021870080 |
| 11 | 30656102400 |
| 12 | 1103619686400 |
| 13 | 44144787456000 |
| 14 | 1854081073152000 |
| 15 | 85287729364992000 |
| 16 | 4434961926979584000 |
| 17 | 257227791764815872000 |
| 18 | 15433667505888952320000 |
[1,1,2,8,48,480,5760,92160,1658880,36495360, 1021870080,30656102400,1103619686400, 44144787456000,1854081073152000,85287729364992000, 4434961926979584000,257227791764815872000, 15433667505888952320000] |