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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 58 |
| 4 | 462 |
| 5 | 3782 |
| 6 | 31436 |
| 7 | 264134 |
| 8 | 2237640 |
| 9 | 19079574 |
| 10 | 163538472 |
| 11 | 1407813438 |
| 12 | 12163015662 |
| 13 | 105407889930 |
| 14 | 915913267652 |
| 15 | 7976914859210 |
| 16 | 69613332125342 |
| 17 | 608590829593638 |
| 18 | 5329041851925256 |
| 19 | 46729591602635246 |
| 20 | 410291878420535354 |
| 21 | 3606612469259086834 |
[1,2,8,58,462,3782,31436,264134,2237640,19079574, 163538472,1407813438,12163015662,105407889930, 915913267652,7976914859210,69613332125342, 608590829593638,5329041851925256, 46729591602635246,410291878420535354, 3606612469259086834] |