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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 16 |
| 3 | 123 |
| 4 | 956 |
| 5 | 7519 |
| 6 | 59742 |
| 7 | 478869 |
| 8 | 3868104 |
| 9 | 31458348 |
| 10 | 257396972 |
| 11 | 2117494621 |
| 12 | 17504651148 |
| 13 | 145341743066 |
| 14 | 1211584784416 |
| 15 | 10136488835157 |
| 16 | 85085339305360 |
| 17 | 716366098507550 |
| 18 | 6048143934750432 |
| 19 | 51194316337883625 |
| 20 | 434360166677159652 |
| 21 | 3693446859517381827 |
[2,16,123,956,7519,59742,478869,3868104,31458348, 257396972,2117494621,17504651148,145341743066, 1211584784416,10136488835157,85085339305360, 716366098507550,6048143934750432, 51194316337883625,434360166677159652, 3693446859517381827] |