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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 7 |
| 3 | 109 |
| 4 | 3088 |
| 5 | 139536 |
| 6 | 9223776 |
| 7 | 839882016 |
| 8 | 100811243520 |
| 9 | 15425745960960 |
| 10 | 2931023414476800 |
| 11 | 677079576933580800 |
| 12 | 186875556584590540800 |
| 13 | 60734785332524728320000 |
| 14 | 22957787631482390937600000 |
| 15 | 9986645219749296609853440000 |
| 16 | 4953377739007903842686730240000 |
| 17 | 2778845349346570753142308208640000 |
[0,1,7,109,3088,139536,9223776,839882016, 100811243520,15425745960960,2931023414476800, 677079576933580800,186875556584590540800, 60734785332524728320000, 22957787631482390937600000, 9986645219749296609853440000, 4953377739007903842686730240000, 2778845349346570753142308208640000] |