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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | 4 |
| 5 | 6 |
| 6 | 32 |
| 7 | 89 |
| 8 | 592 |
| 9 | 2402 |
| 10 | 19072 |
| 11 | 101866 |
| 12 | 939136 |
| 13 | 6221228 |
| 14 | 65291264 |
| 15 | 516212409 |
| 16 | 6075261184 |
| 17 | 55812055946 |
| 18 | 727912302592 |
| 19 | 7618369901774 |
| 20 | 109058247342080 |
| 21 | 1280820543489044 |
| 22 | 19965414947799040 |
| 23 | 259988000952099210 |
| 24 | 4383593333171363840 |
| 25 | 62680335913868539796 |
[1,1,2,1,4,6,32,89,592,2402,19072,101866,939136, 6221228,65291264,516212409,6075261184,55812055946, 727912302592,7618369901774,109058247342080, 1280820543489044,19965414947799040, 259988000952099210,4383593333171363840, 62680335913868539796] |