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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 32 |
| 4 | 176 |
| 5 | 1126 |
| 6 | 8227 |
| 7 | 67768 |
| 8 | 622706 |
| 9 | 6323932 |
| 10 | 70400734 |
| 11 | 852952952 |
| 12 | 11176241098 |
| 13 | 157506733030 |
| 14 | 2375966883371 |
| 15 | 38200984291800 |
| 16 | 652179787654530 |
| 17 | 11783182484950980 |
| 18 | 224623760504277810 |
| 19 | 4505795627243046240 |
| 20 | 94873821120923655336 |
| 21 | 2092249161797280567516 |
[1,2,7,32,176,1126,8227,67768,622706,6323932, 70400734,852952952,11176241098,157506733030, 2375966883371,38200984291800,652179787654530, 11783182484950980,224623760504277810, 4505795627243046240,94873821120923655336, 2092249161797280567516] |