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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 474 |
| 3 | 2796 |
| 4 | 16588 |
| 5 | 98368 |
| 6 | 582304 |
| 7 | 3448740 |
| 8 | 20433016 |
| 9 | 121047396 |
| 10 | 716976816 |
| 11 | 4246991476 |
| 12 | 25158285744 |
| 13 | 149029929508 |
| 14 | 882785392368 |
| 15 | 5229257584788 |
| 16 | 30976260240096 |
| 17 | 183491943495380 |
| 18 | 1086934090832432 |
| 19 | 6438575430083476 |
[81,474,2796,16588,98368,582304,3448740,20433016, 121047396,716976816,4246991476,25158285744, 149029929508,882785392368,5229257584788, 30976260240096,183491943495380,1086934090832432, 6438575430083476] |