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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 55 |
| 5 | 562 |
| 6 | 7739 |
| 7 | 134808 |
| 8 | 2846764 |
| 9 | 70720278 |
| 10 | 2021462055 |
| 11 | 65365925308 |
| 12 | 2359387012261 |
| 13 | 94042995460130 |
| 14 | 4102781803365418 |
| 15 | 194459091322828280 |
| 16 | 9950303194613104995 |
| 17 | 546698973373090998382 |
| 18 | 32101070021048906407183 |
| 19 | 2006125858248695722280564 |
[1,1,2,8,55,562,7739,134808,2846764,70720278, 2021462055,65365925308,2359387012261, 94042995460130,4102781803365418, 194459091322828280,9950303194613104995, 546698973373090998382,32101070021048906407183, 2006125858248695722280564] |