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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 270 |
| 3 | 750 |
| 4 | 2244 |
| 5 | 4944 |
| 6 | 11712 |
| 7 | 35904 |
| 8 | 79104 |
| 9 | 187392 |
| 10 | 574464 |
| 11 | 1265664 |
| 12 | 2998272 |
| 13 | 9191424 |
| 14 | 20250624 |
| 15 | 47972352 |
| 16 | 147062784 |
| 17 | 324009984 |
| 18 | 767557632 |
| 19 | 2353004544 |
| 20 | 5184159744 |
| 21 | 12280922112 |
| 22 | 37648072704 |
| 23 | 82946555904 |
| 24 | 196494753792 |
[81,270,750,2244,4944,11712,35904,79104,187392, 574464,1265664,2998272,9191424,20250624,47972352, 147062784,324009984,767557632,2353004544, 5184159744,12280922112,37648072704,82946555904, 196494753792] |