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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 15 |
| 4 | 47 |
| 5 | 159 |
| 6 | 567 |
| 7 | 2079 |
| 8 | 7920 |
| 9 | 30827 |
| 10 | 122432 |
| 11 | 495884 |
| 12 | 2034691 |
| 13 | 8466701 |
| 14 | 35632214 |
| 15 | 151397685 |
| 16 | 649417899 |
| 17 | 2806992134 |
| 18 | 12221505766 |
| 19 | 53565228368 |
| 20 | 236125050931 |
| 21 | 1046671869520 |
| 22 | 4662417859457 |
| 23 | 20863697406632 |
| 24 | 93761573243960 |
| 25 | 422995742344138 |
| 26 | 1915298621788458 |
| 27 | 8701706539380666 |
[1,2,5,15,47,159,567,2079,7920,30827,122432, 495884,2034691,8466701,35632214,151397685, 649417899,2806992134,12221505766,53565228368, 236125050931,1046671869520,4662417859457, 20863697406632,93761573243960,422995742344138, 1915298621788458,8701706539380666] |