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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 21 |
| 6 | 50 |
| 7 | 99 |
| 8 | 250 |
| 9 | 454 |
| 10 | 1242 |
| 11 | 2223 |
| 12 | 6394 |
| 13 | 11389 |
| 14 | 35002 |
| 15 | 62034 |
| 16 | 202010 |
| 17 | 359483 |
| 18 | 1233518 |
| 19 | 2203507 |
| 20 | 7944110 |
| 21 | 14249736 |
| 22 | 53811584 |
| 23 | 96912709 |
| 24 | 382289362 |
| 25 | 691110821 |
| 26 | 2841057442 |
| 27 | 5154280744 |
| 28 | 22033974854 |
| 29 | 40105797777 |
| 30 | 177946445580 |
[1,1,2,4,10,21,50,99,250,454,1242,2223,6394,11389, 35002,62034,202010,359483,1233518,2203507,7944110, 14249736,53811584,96912709,382289362,691110821, 2841057442,5154280744,22033974854,40105797777, 177946445580] |