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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 31 |
| 4 | 159 |
| 5 | 955 |
| 6 | 6677 |
| 7 | 51308 |
| 8 | 429868 |
| 9 | 3847548 |
| 10 | 36599474 |
| 11 | 366515450 |
| 12 | 3848812068 |
| 13 | 42154442638 |
| 14 | 480103999452 |
| 15 | 5666303543327 |
| 16 | 69139729751267 |
| 17 | 870092119451903 |
| 18 | 11272494698299169 |
| 19 | 150074841511853609 |
[1,2,8,31,159,955,6677,51308,429868,3847548, 36599474,366515450,3848812068,42154442638, 480103999452,5666303543327,69139729751267, 870092119451903,11272494698299169, 150074841511853609] |