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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 34 |
| 5 | 173 |
| 6 | 1040 |
| 7 | 7285 |
| 8 | 58280 |
| 9 | 524525 |
| 10 | 5245250 |
| 11 | 57697759 |
| 12 | 692373112 |
| 13 | 9000850463 |
| 14 | 126011906488 |
| 15 | 1890178597320 |
| 16 | 30242857557129 |
| 17 | 514128578471206 |
| 18 | 9254314412481710 |
| 19 | 175831973837152494 |
| 20 | 3516639476743049893 |
[1,2,8,34,173,1040,7285,58280,524525,5245250, 57697759,692373112,9000850463,126011906488, 1890178597320,30242857557129,514128578471206, 9254314412481710,175831973837152494, 3516639476743049893] |