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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 23 |
| 4 | 55 |
| 5 | 144 |
| 6 | 328 |
| 7 | 816 |
| 8 | 1808 |
| 9 | 4358 |
| 10 | 9485 |
| 11 | 22377 |
| 12 | 48097 |
| 13 | 111720 |
| 14 | 237917 |
| 15 | 546161 |
| 16 | 1154827 |
| 17 | 2626624 |
| 18 | 5522464 |
| 19 | 12467540 |
| 20 | 26092324 |
| 21 | 58546544 |
| 22 | 122059348 |
| 23 | 272479782 |
| 24 | 566242186 |
| 25 | 1258568324 |
| 26 | 2608232758 |
| 27 | 5775620396 |
| 28 | 11940756076 |
[1,3,8,23,55,144,328,816,1808,4358,9485,22377, 48097,111720,237917,546161,1154827,2626624, 5522464,12467540,26092324,58546544,122059348, 272479782,566242186,1258568324,2608232758, 5775620396,11940756076] |