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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 16 |
| 3 | 45 |
| 4 | 135 |
| 5 | 544 |
| 6 | 1765 |
| 7 | 5763 |
| 8 | 20811 |
| 9 | 70207 |
| 10 | 236330 |
| 11 | 822902 |
| 12 | 2806042 |
| 13 | 9547539 |
| 14 | 32855983 |
| 15 | 112351535 |
| 16 | 383730987 |
| 17 | 1315580367 |
| 18 | 4501742568 |
| 19 | 15396061261 |
| 20 | 52720880494 |
| 21 | 180431027632 |
| 22 | 617365998304 |
| 23 | 2113260768118 |
| 24 | 7232567686580 |
[3,16,45,135,544,1765,5763,20811,70207,236330, 822902,2806042,9547539,32855983,112351535, 383730987,1315580367,4501742568,15396061261, 52720880494,180431027632,617365998304, 2113260768118,7232567686580] |