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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 6 |
| 3 | 16 |
| 4 | 39 |
| 5 | 99 |
| 6 | 248 |
| 7 | 622 |
| 8 | 1559 |
| 9 | 3907 |
| 10 | 9793 |
| 11 | 24546 |
| 12 | 61529 |
| 13 | 154230 |
| 14 | 386598 |
| 15 | 969056 |
| 16 | 2429064 |
| 17 | 6088760 |
| 18 | 15262259 |
| 19 | 38256810 |
| 20 | 95895601 |
| 21 | 240374624 |
| 22 | 602529829 |
| 23 | 1510318305 |
| 24 | 3785806568 |
| 25 | 9489609784 |
| 26 | 23786924201 |
| 27 | 59624976768 |
| 28 | 149457652642 |
| 29 | 374634777972 |
[1,3,6,16,39,99,248,622,1559,3907,9793,24546, 61529,154230,386598,969056,2429064,6088760, 15262259,38256810,95895601,240374624,602529829, 1510318305,3785806568,9489609784,23786924201, 59624976768,149457652642,374634777972] |