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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 11 |
| 3 | 60 |
| 4 | 365 |
| 5 | 2350 |
| 6 | 15767 |
| 7 | 109048 |
| 8 | 771993 |
| 9 | 5567066 |
| 10 | 40751267 |
| 11 | 302018484 |
| 12 | 2261763205 |
| 13 | 17088919814 |
| 14 | 130108591407 |
| 15 | 997225521136 |
| 16 | 7688232599089 |
| 17 | 59581977618098 |
| 18 | 463890112373563 |
| 19 | 3626778446099756 |
| 20 | 28461425971969693 |
| 21 | 224114796803735774 |
| 22 | 1770236735807921863 |
[1,2,11,60,365,2350,15767,109048,771993,5567066, 40751267,302018484,2261763205,17088919814, 130108591407,997225521136,7688232599089, 59581977618098,463890112373563,3626778446099756, 28461425971969693,224114796803735774, 1770236735807921863] |