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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 4 |
| 6 | 5 |
| 7 | 6 |
| 8 | 41 |
| 9 | 208 |
| 10 | 711 |
| 11 | 1970 |
| 12 | 4741 |
| 13 | 10284 |
| 14 | 123397 |
| 15 | 1041224 |
| 16 | 5690415 |
| 17 | 24359248 |
| 18 | 87922385 |
| 19 | 278723178 |
| 20 | 4777712981 |
| 21 | 56439873880 |
| 22 | 424119250083 |
| 23 | 2456329637366 |
| 24 | 11821181689417 |
| 25 | 49308397822776 |
| 26 | 1098781192727401 |
| 27 | 16688667550625072 |
| 28 | 159609583197355203 |
[1,1,1,2,3,4,5,6,41,208,711,1970,4741,10284, 123397,1041224,5690415,24359248,87922385, 278723178,4777712981,56439873880,424119250083, 2456329637366,11821181689417,49308397822776, 1098781192727401,16688667550625072, 159609583197355203] |