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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 10 |
| 4 | 36 |
| 5 | 136 |
| 6 | 548 |
| 7 | 2316 |
| 8 | 10050 |
| 9 | 44426 |
| 10 | 199666 |
| 11 | 910090 |
| 12 | 4196984 |
| 13 | 19545844 |
| 14 | 91791112 |
| 15 | 434181656 |
| 16 | 2066656564 |
| 17 | 9891669820 |
| 18 | 47578282002 |
| 19 | 229858639366 |
| 20 | 1114895656402 |
| 21 | 5427058308018 |
| 22 | 26503888167186 |
| 23 | 129821343271168 |
| 24 | 637626106479490 |
[1,2,4,10,36,136,548,2316,10050,44426,199666, 910090,4196984,19545844,91791112,434181656, 2066656564,9891669820,47578282002,229858639366, 1114895656402,5427058308018,26503888167186, 129821343271168,637626106479490] |