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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 20 |
| 7 | 48 |
| 8 | 115 |
| 9 | 285 |
| 10 | 710 |
| 11 | 1789 |
| 12 | 4514 |
| 13 | 11431 |
| 14 | 28922 |
| 15 | 73182 |
| 16 | 184917 |
| 17 | 466755 |
| 18 | 1176393 |
| 19 | 2961205 |
| 20 | 7443770 |
| 21 | 18689435 |
| 22 | 46869152 |
| 23 | 117412440 |
| 24 | 293832126 |
| 25 | 734645046 |
| 26 | 1835147741 |
| 27 | 4580420719 |
| 28 | 11423511895 |
| 29 | 28469058647 |
| 30 | 70899220083 |
| 31 | 176449174539 |
| 32 | 438854372942 |
[1,1,1,2,4,9,20,48,115,285,710,1789,4514,11431, 28922,73182,184917,466755,1176393,2961205,7443770, 18689435,46869152,117412440,293832126,734645046, 1835147741,4580420719,11423511895,28469058647, 70899220083,176449174539,438854372942] |