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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 20 |
| 6 | 47 |
| 7 | 112 |
| 8 | 274 |
| 9 | 679 |
| 10 | 1708 |
| 11 | 4341 |
| 12 | 11143 |
| 13 | 28831 |
| 14 | 75135 |
| 15 | 197013 |
| 16 | 519447 |
| 17 | 1376256 |
| 18 | 3662327 |
| 19 | 9784106 |
| 20 | 26232033 |
| 21 | 70558313 |
| 22 | 190348160 |
| 23 | 514904151 |
| 24 | 1396328313 |
| 25 | 3795324358 |
| 26 | 10338000693 |
| 27 | 28215285901 |
| 28 | 77149545999 |
| 29 | 211314835549 |
| 30 | 579730469034 |
[1,1,2,4,9,20,47,112,274,679,1708,4341,11143, 28831,75135,197013,519447,1376256,3662327,9784106, 26232033,70558313,190348160,514904151,1396328313, 3795324358,10338000693,28215285901,77149545999, 211314835549,579730469034] |