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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 30 |
| 4 | 113 |
| 5 | 428 |
| 6 | 1629 |
| 7 | 6226 |
| 8 | 23881 |
| 9 | 91884 |
| 10 | 354484 |
| 11 | 1370812 |
| 12 | 5312058 |
| 13 | 20622904 |
| 14 | 80196055 |
| 15 | 312319530 |
| 16 | 1217938665 |
| 17 | 4755296460 |
| 18 | 18586968840 |
| 19 | 72723903780 |
| 20 | 284804791230 |
| 21 | 1116315593640 |
| 22 | 4378929921210 |
| 23 | 17189573707956 |
[1,2,8,30,113,428,1629,6226,23881,91884,354484, 1370812,5312058,20622904,80196055,312319530, 1217938665,4755296460,18586968840,72723903780, 284804791230,1116315593640,4378929921210, 17189573707956] |