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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 10 |
| 4 | 59 |
| 5 | 385 |
| 6 | 2672 |
| 7 | 19336 |
| 8 | 144218 |
| 9 | 1100530 |
| 10 | 8549888 |
| 11 | 67386652 |
| 12 | 537437222 |
| 13 | 4328934754 |
| 14 | 35162809688 |
| 15 | 287688325672 |
| 16 | 2368563539171 |
| 17 | 19608128003473 |
| 18 | 163116600371846 |
| 19 | 1362822870625762 |
| 20 | 11430476370562259 |
[1,2,10,59,385,2672,19336,144218,1100530,8549888, 67386652,537437222,4328934754,35162809688, 287688325672,2368563539171,19608128003473, 163116600371846,1362822870625762, 11430476370562259] |