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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 8 |
| 3 | 2 |
| 4 | 47 |
| 5 | 207 |
| 6 | 1417 |
| 7 | 7538 |
| 8 | 53989 |
| 9 | 309136 |
| 10 | 2041378 |
| 11 | 12561807 |
| 12 | 80107485 |
| 13 | 503096639 |
| 14 | 3184635107 |
| 15 | 20059337678 |
| 16 | 126810474201 |
| 17 | 799559544897 |
| 18 | 5050657497454 |
| 19 | 31866050738166 |
| 20 | 201192109912331 |
| 21 | 1269778066786642 |
| 22 | 8015596643008521 |
[0,8,2,47,207,1417,7538,53989,309136,2041378, 12561807,80107485,503096639,3184635107, 20059337678,126810474201,799559544897, 5050657497454,31866050738166,201192109912331, 1269778066786642,8015596643008521] |