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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 31 |
| 6 | 92 |
| 7 | 283 |
| 8 | 893 |
| 9 | 2875 |
| 10 | 9407 |
| 11 | 31189 |
| 12 | 104555 |
| 13 | 353794 |
| 14 | 1206821 |
| 15 | 4145350 |
| 16 | 14326184 |
| 17 | 49778473 |
| 18 | 173794610 |
| 19 | 609392578 |
| 20 | 2145057797 |
| 21 | 7577098816 |
| 22 | 26850456704 |
| 23 | 95425761829 |
| 24 | 340047930692 |
| 25 | 1214738997142 |
| 26 | 4349231444405 |
| 27 | 15604726428805 |
| 28 | 56098211626478 |
[1,1,2,4,11,31,92,283,893,2875,9407,31189,104555, 353794,1206821,4145350,14326184,49778473, 173794610,609392578,2145057797,7577098816, 26850456704,95425761829,340047930692, 1214738997142,4349231444405,15604726428805, 56098211626478] |