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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 6 |
| 2 | 30 |
| 3 | 189 |
| 4 | 1350 |
| 5 | 10395 |
| 6 | 58046625 |
| 7 | 1403325 |
| 8 | 21709437750 |
| 9 | 2292899734125 |
| 10 | 80596287646875 |
| 11 | 640374140030625 |
| 12 | 8779111824511153125 |
| 13 | 443779279041223125 |
| 14 | 20913098524817639765625 |
| 15 | 195202717402382161174828125 |
| 16 | 2015813566807172297008593750 |
| 17 | 367589532770719654160390625 |
[2,6,30,189,1350,10395,58046625,1403325, 21709437750,2292899734125,80596287646875, 640374140030625,8779111824511153125, 443779279041223125,20913098524817639765625, 195202717402382161174828125, 2015813566807172297008593750, 367589532770719654160390625] |