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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 8 |
| 3 | 51 |
| 4 | 295 |
| 5 | 1632 |
| 6 | 8830 |
| 7 | 47239 |
| 8 | 251261 |
| 9 | 1332456 |
| 10 | 7055228 |
| 11 | 37327007 |
| 12 | 197404203 |
| 13 | 1043751584 |
| 14 | 5518106750 |
| 15 | 29171471659 |
| 16 | 154210451661 |
| 17 | 815197197636 |
| 18 | 4309313949364 |
| 19 | 22779900825195 |
| 20 | 120418887728947 |
[1,8,51,295,1632,8830,47239,251261,1332456, 7055228,37327007,197404203,1043751584,5518106750, 29171471659,154210451661,815197197636, 4309313949364,22779900825195,120418887728947] |