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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 22 |
| 4 | 56 |
| 5 | 121 |
| 6 | 603 |
| 7 | 4292 |
| 8 | 34905 |
| 9 | 284158 |
| 10 | 2388099 |
| 11 | 29265021 |
| 12 | 473031984 |
| 13 | 9304582753 |
| 14 | 212580151667 |
| 15 | 5654131835907 |
| 16 | 189056293870086 |
| 17 | 7909530731661434 |
[1,2,7,22,56,121,603,4292,34905,284158,2388099, 29265021,473031984,9304582753,212580151667, 5654131835907,189056293870086,7909530731661434] |