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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 10 |
| 4 | 42 |
| 5 | 251 |
| 6 | 1811 |
| 7 | 18978 |
| 8 | 336604 |
| 9 | 7870292 |
| 10 | 267729787 |
| 11 | 13016021132 |
[1,5,10,42,251,1811,18978,336604,7870292, 267729787,13016021132] |