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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 344 |
| 3 | 1488 |
| 4 | 6496 |
| 5 | 28176 |
| 6 | 121088 |
| 7 | 523776 |
| 8 | 2286592 |
| 9 | 9917952 |
| 10 | 42622976 |
| 11 | 184369152 |
| 12 | 804880384 |
| 13 | 3491119104 |
| 14 | 15003287552 |
| 15 | 64897941504 |
| 16 | 283317895168 |
| 17 | 1228873924608 |
| 18 | 5281157218304 |
| 19 | 22844075409408 |
| 20 | 99727899099136 |
| 21 | 432563621462016 |
[81,344,1488,6496,28176,121088,523776,2286592, 9917952,42622976,184369152,804880384,3491119104, 15003287552,64897941504,283317895168, 1228873924608,5281157218304,22844075409408, 99727899099136,432563621462016] |