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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 23 |
| 4 | 201 |
| 5 | 2785 |
| 6 | 40635 |
| 7 | 811895 |
| 8 | 16629585 |
| 9 | 433628545 |
| 10 | 11445940275 |
| 11 | 368037044375 |
| 12 | 11895934275225 |
| 13 | 454683830425825 |
| 14 | 17395789407271275 |
| 15 | 770304889659680375 |
| 16 | 34049461218930782625 |
| 17 | 1713856100186247642625 |
| 18 | 85952505988900976299875 |
| 19 | 4846232366161595854820375 |
[1,1,3,23,201,2785,40635,811895,16629585, 433628545,11445940275,368037044375,11895934275225, 454683830425825,17395789407271275, 770304889659680375,34049461218930782625, 1713856100186247642625,85952505988900976299875, 4846232366161595854820375] |