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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 18 |
| 5 | 62 |
| 6 | 238 |
| 7 | 916 |
| 8 | 3706 |
| 9 | 15243 |
| 10 | 64409 |
| 11 | 276189 |
| 12 | 1203838 |
| 13 | 5305479 |
| 14 | 23641944 |
| 15 | 106267870 |
| 16 | 481560161 |
| 17 | 2197119864 |
| 18 | 10086780977 |
| 19 | 46558844757 |
| 20 | 215964339529 |
| 21 | 1006146037229 |
| 22 | 4706126682598 |
| 23 | 22091433526799 |
| 24 | 104041065742422 |
| 25 | 491452327197918 |
| 26 | 2327802367903136 |
| 27 | 11053557370505303 |
| 28 | 52609476576750227 |
[1,1,2,5,18,62,238,916,3706,15243,64409,276189, 1203838,5305479,23641944,106267870,481560161, 2197119864,10086780977,46558844757,215964339529, 1006146037229,4706126682598,22091433526799, 104041065742422,491452327197918,2327802367903136, 11053557370505303,52609476576750227] |