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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 126 |
| 5 | 2170 |
| 6 | 37335 |
| 7 | 921333 |
| 8 | 21967484 |
| 9 | 466292604 |
| 10 | 9161931075 |
| 11 | 164162481681 |
| 12 | 2705726857350 |
| 13 | 41747317681290 |
| 14 | 619096670144225 |
| 15 | 8923605271290360 |
| 16 | 124998845674120920 |
| 17 | 1699006653803990456 |
| 18 | 22382667992161145863 |
[1,3,126,2170,37335,921333,21967484,466292604, 9161931075,164162481681,2705726857350, 41747317681290,619096670144225,8923605271290360, 124998845674120920,1699006653803990456, 22382667992161145863] |