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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 151 |
| 4 | 502 |
| 5 | 2719 |
| 6 | 11341 |
| 7 | 82549 |
| 8 | 396787 |
| 9 | 2346541 |
| 10 | 11876657 |
| 11 | 70286741 |
| 12 | 374560274 |
| 13 | 2145325624 |
| 14 | 11643190391 |
| 15 | 66070482072 |
| 16 | 363830683327 |
| 17 | 2050031109245 |
| 18 | 11362362156585 |
| 19 | 63803460702931 |
| 20 | 355097907791024 |
| 21 | 1990234603016555 |
[1,6,151,502,2719,11341,82549,396787,2346541, 11876657,70286741,374560274,2145325624, 11643190391,66070482072,363830683327, 2050031109245,11362362156585,63803460702931, 355097907791024,1990234603016555] |