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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 181 |
| 3 | 3322 |
| 4 | 72540 |
| 5 | 1845480 |
| 6 | 53749920 |
| 7 | 1766525760 |
| 8 | 64739122560 |
| 9 | 2619453513600 |
| 10 | 116043825744000 |
| 11 | 5588681114016000 |
| 12 | 290812286052288000 |
| 13 | 16263827918642304000 |
| 14 | 973009916329651200000 |
| 15 | 62017234027123415040000 |
| 16 | 4195886889891954216960000 |
[1,12,181,3322,72540,1845480,53749920,1766525760, 64739122560,2619453513600,116043825744000, 5588681114016000,290812286052288000, 16263827918642304000,973009916329651200000, 62017234027123415040000,4195886889891954216960000] |