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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 5 |
| 6 | 23 |
| 7 | 196 |
| 8 | 2813 |
| 9 | 65961 |
| 10 | 2461846 |
| 11 | 142900605 |
| 12 | 12629963362 |
| 13 | 1667181039425 |
| 14 | 322952216807258 |
| 15 | 90343400059852993 |
| 16 | 35964677954267885714 |
| 17 | 20101122321919710856624 |
| 18 | 15578877275203698667362792 |
| 19 | 16551744087124668098653612165 |
[1,1,1,1,2,5,23,196,2813,65961,2461846,142900605, 12629963362,1667181039425,322952216807258, 90343400059852993,35964677954267885714, 20101122321919710856624, 15578877275203698667362792, 16551744087124668098653612165] |