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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 14 |
| 3 | 128 |
| 4 | 1310 |
| 5 | 14252 |
| 6 | 161168 |
| 7 | 1872096 |
| 8 | 22179102 |
| 9 | 266766500 |
| 10 | 3247293764 |
| 11 | 39914850560 |
| 12 | 494587904720 |
| 13 | 6170138404640 |
| 14 | 77420709800000 |
| 15 | 976308769560128 |
| 16 | 12365391374849310 |
| 17 | 157214288994620820 |
| 18 | 2005631418267291740 |
[1,2,14,128,1310,14252,161168,1872096,22179102, 266766500,3247293764,39914850560,494587904720, 6170138404640,77420709800000,976308769560128, 12365391374849310,157214288994620820, 2005631418267291740] |