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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 294 |
| 3 | 905 |
| 4 | 2584 |
| 5 | 7353 |
| 6 | 20800 |
| 7 | 58896 |
| 8 | 167240 |
| 9 | 474948 |
| 10 | 1344000 |
| 11 | 3811120 |
| 12 | 10818624 |
| 13 | 30677136 |
| 14 | 86900480 |
| 15 | 246546816 |
| 16 | 699399552 |
| 17 | 1982514496 |
| 18 | 5620085760 |
| 19 | 15943384320 |
| 20 | 45209722880 |
| 21 | 128165455104 |
| 22 | 363441340416 |
| 23 | 1030800314368 |
| 24 | 2922637780992 |
[81,294,905,2584,7353,20800,58896,167240,474948, 1344000,3811120,10818624,30677136,86900480, 246546816,699399552,1982514496,5620085760, 15943384320,45209722880,128165455104,363441340416, 1030800314368,2922637780992] |