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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 6 |
| 6 | 31 |
| 7 | 146 |
| 8 | 655 |
| 9 | 2850 |
| 10 | 12148 |
| 11 | 51028 |
| 12 | 212039 |
| 13 | 873870 |
| 14 | 3578404 |
| 15 | 14578576 |
| 16 | 59149381 |
| 17 | 239177006 |
| 18 | 964439355 |
| 19 | 3879856458 |
| 20 | 15577609711 |
| 21 | 62439489346 |
| 22 | 249917575553 |
| 23 | 999080441830 |
| 24 | 3989726087031 |
| 25 | 15917901326330 |
| 26 | 63457122234055 |
| 27 | 252796365476922 |
| 28 | 1006456231070795 |
| 29 | 4004838954237250 |
| 30 | 15928299669867291 |
[1,6,31,146,655,2850,12148,51028,212039,873870, 3578404,14578576,59149381,239177006,964439355, 3879856458,15577609711,62439489346,249917575553, 999080441830,3989726087031,15917901326330, 63457122234055,252796365476922,1006456231070795, 4004838954237250,15928299669867291] |