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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 10 |
| 2 | 115 |
| 3 | 1450 |
| 4 | 19425 |
| 5 | 271502 |
| 6 | 3915100 |
| 7 | 57821940 |
| 8 | 870238200 |
| 9 | 13298907050 |
| 10 | 205811513765 |
| 11 | 3218995093860 |
| 12 | 50802419972395 |
| 13 | 808016193159000 |
| 14 | 12938696992921000 |
| 15 | 208419656266988904 |
| 16 | 3374960506795660365 |
| 17 | 54907659530154222000 |
| 18 | 897060906625956765000 |
[1,10,115,1450,19425,271502,3915100,57821940, 870238200,13298907050,205811513765,3218995093860, 50802419972395,808016193159000,12938696992921000, 208419656266988904,3374960506795660365, 54907659530154222000,897060906625956765000] |