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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 268 |
| 3 | 928 |
| 4 | 2784 |
| 5 | 9628 |
| 6 | 28912 |
| 7 | 100008 |
| 8 | 300256 |
| 9 | 1038560 |
| 10 | 3118208 |
| 11 | 10785696 |
| 12 | 32383104 |
| 13 | 112011072 |
| 14 | 336303872 |
| 15 | 1163253760 |
| 16 | 3492571136 |
| 17 | 12080581376 |
| 18 | 36270926848 |
| 19 | 125458829824 |
| 20 | 376679553024 |
| 21 | 1302910621696 |
| 22 | 3911879237632 |
[81,268,928,2784,9628,28912,100008,300256,1038560, 3118208,10785696,32383104,112011072,336303872, 1163253760,3492571136,12080581376,36270926848, 125458829824,376679553024,1302910621696, 3911879237632] |