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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 30 |
| 4 | 174 |
| 5 | 1102 |
| 6 | 8004 |
| 7 | 64908 |
| 8 | 631296 |
| 9 | 7632144 |
| 10 | 85538304 |
| 11 | 767957760 |
| 12 | 10378782720 |
| 13 | 141810600960 |
| 14 | 2211872624640 |
| 15 | 34073996544000 |
| 16 | 592443113472000 |
| 17 | 9995136528384000 |
| 18 | 193299238895616000 |
| 19 | 3978509063587430400 |
[1,5,30,174,1102,8004,64908,631296,7632144, 85538304,767957760,10378782720,141810600960, 2211872624640,34073996544000,592443113472000, 9995136528384000,193299238895616000, 3978509063587430400] |