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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 0 |
| 3 | 3 |
| 4 | 4 |
| 5 | 8 |
| 6 | 6 |
| 7 | 15 |
| 8 | 18 |
| 9 | 45 |
| 10 | 118 |
| 11 | 553 |
| 12 | 1706 |
| 13 | 2845 |
| 14 | 2970 |
| 15 | 4470 |
| 16 | 9426 |
| 17 | 30908 |
| 18 | 115084 |
| 19 | 350693 |
| 20 | 804152 |
| 21 | 1724453 |
| 22 | 3598260 |
| 23 | 6467166 |
| 24 | 12292306 |
| 25 | 36973565 |
| 26 | 137754308 |
| 27 | 493838258 |
| 28 | 1570992174 |
| 29 | 4107583256 |
| 30 | 8556975584 |
| 31 | 14790344176 |
| 32 | 23129972292 |
[2,0,3,4,8,6,15,18,45,118,553,1706,2845,2970,4470, 9426,30908,115084,350693,804152,1724453,3598260, 6467166,12292306,36973565,137754308,493838258, 1570992174,4107583256,8556975584,14790344176, 23129972292] |