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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 6 |
| 3 | 70 |
| 4 | 2030 |
| 5 | 42978 |
| 6 | 1788710 |
| 7 | 63905142 |
| 8 | 5705962314 |
| 9 | 888081948858 |
| 10 | 120056591419170 |
[3,6,70,2030,42978,1788710,63905142,5705962314, 888081948858,120056591419170] |