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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 13 |
| 5 | 36 |
| 6 | 126 |
| 7 | 428 |
| 8 | 1681 |
| 9 | 6820 |
| 10 | 29233 |
| 11 | 127865 |
| 12 | 592604 |
| 13 | 2829477 |
| 14 | 14118079 |
| 15 | 72122117 |
| 16 | 380843081 |
| 17 | 2056927326 |
| 18 | 11444517369 |
| 19 | 65234523659 |
| 20 | 380644223976 |
| 21 | 2272831229113 |
| 22 | 13857568536672 |
| 23 | 86164285623173 |
| 24 | 546196787212398 |
[1,2,4,13,36,126,428,1681,6820,29233,127865, 592604,2829477,14118079,72122117,380843081, 2056927326,11444517369,65234523659,380644223976, 2272831229113,13857568536672,86164285623173, 546196787212398] |