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| n | a(n) |
|---|---|
| 4 | 3 |
| 5 | 11 |
| 6 | 37 |
| 7 | 124 |
| 8 | 420 |
| 9 | 1441 |
| 10 | 5005 |
| 11 | 17576 |
| 12 | 62322 |
| 13 | 222870 |
| 14 | 802978 |
| 15 | 2912168 |
| 16 | 10623470 |
| 17 | 38956365 |
| 18 | 143521725 |
| 19 | 530985360 |
| 20 | 1971965490 |
| 21 | 7348812570 |
| 22 | 27472909590 |
| 23 | 103002205800 |
| 24 | 387205269360 |
| 25 | 1459146890058 |
| 26 | 5511120747282 |
| 27 | 20858962792624 |
| 28 | 79103096214100 |
[3,11,37,124,420,1441,5005,17576,62322,222870, 802978,2912168,10623470,38956365,143521725, 530985360,1971965490,7348812570,27472909590, 103002205800,387205269360,1459146890058, 5511120747282,20858962792624,79103096214100] |