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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 27 |
| 3 | 244 |
| 4 | 2187 |
| 5 | 19684 |
| 6 | 177147 |
| 7 | 1594324 |
| 8 | 14348907 |
| 9 | 129140164 |
| 10 | 1162261467 |
| 11 | 10460353204 |
| 12 | 94143178827 |
| 13 | 847288609444 |
| 14 | 7625597484987 |
| 15 | 68630377364884 |
| 16 | 617673396283947 |
| 17 | 5559060566555524 |
| 18 | 50031545098999707 |
| 19 | 450283905890997364 |
[4,27,244,2187,19684,177147,1594324,14348907, 129140164,1162261467,10460353204,94143178827, 847288609444,7625597484987,68630377364884, 617673396283947,5559060566555524, 50031545098999707,450283905890997364] |