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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 26 |
| 6 | 80 |
| 7 | 251 |
| 8 | 929 |
| 9 | 3727 |
| 10 | 17565 |
| 11 | 95428 |
| 12 | 629795 |
| 13 | 5171063 |
| 14 | 55857762 |
| 15 | 831428458 |
| 16 | 17625946914 |
[1,2,4,11,26,80,251,929,3727,17565,95428,629795, 5171063,55857762,831428458,17625946914] |