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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 24 |
| 5 | 1080 |
| 6 | 52440 |
| 7 | 3281880 |
| 8 | 277953144 |
| 9 | 32418855000 |
| 10 | 5239070305080 |
| 11 | 1173944480658840 |
| 12 | 363936227764858584 |
| 13 | 155521768202208047640 |
| 14 | 91218870039317505477720 |
| 15 | 73113879800794757415243480 |
| 16 | 79743817918540500914682249144 |
| 17 | 117883366412734188786535902826200 |
| 18 | 235329353612778837110901775412557560 |
[1,1,0,0,24,1080,52440,3281880,277953144, 32418855000,5239070305080,1173944480658840, 363936227764858584,155521768202208047640, 91218870039317505477720, 73113879800794757415243480, 79743817918540500914682249144, 117883366412734188786535902826200, 235329353612778837110901775412557560] |