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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 27 |
| 7 | 77 |
| 8 | 226 |
| 9 | 685 |
| 10 | 2112 |
| 11 | 6618 |
| 12 | 20996 |
| 13 | 67337 |
| 14 | 217884 |
| 15 | 710571 |
| 16 | 2332958 |
| 17 | 7705429 |
| 18 | 25584035 |
| 19 | 85346018 |
| 20 | 285908169 |
| 21 | 961440343 |
| 22 | 3244259406 |
| 23 | 10981797187 |
| 24 | 37280278698 |
| 25 | 126890974820 |
| 26 | 432950169885 |
| 27 | 1480542159038 |
| 28 | 5073504809660 |
[1,1,2,4,10,27,77,226,685,2112,6618,20996,67337, 217884,710571,2332958,7705429,25584035,85346018, 285908169,961440343,3244259406,10981797187, 37280278698,126890974820,432950169885, 1480542159038,5073504809660] |