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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 39 |
| 6 | 170 |
| 7 | 788 |
| 8 | 3885 |
| 9 | 20060 |
| 10 | 107989 |
| 11 | 603762 |
| 12 | 3496305 |
| 13 | 20943217 |
| 14 | 129663393 |
| 15 | 829488918 |
| 16 | 5483243950 |
| 17 | 37460570247 |
| 18 | 264551156875 |
| 19 | 1931501448369 |
| 20 | 14578396143512 |
| 21 | 113720726834349 |
| 22 | 916367532085433 |
| 23 | 7622370642112803 |
| 24 | 65390072935144713 |
| 25 | 577947703151643232 |
[1,1,1,3,10,39,170,788,3885,20060,107989,603762, 3496305,20943217,129663393,829488918,5483243950, 37460570247,264551156875,1931501448369, 14578396143512,113720726834349,916367532085433, 7622370642112803,65390072935144713, 577947703151643232] |