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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 38 |
| 5 | 279 |
| 6 | 2535 |
| 7 | 27106 |
| 8 | 330998 |
| 9 | 4526827 |
| 10 | 68402684 |
| 11 | 1130591607 |
| 12 | 20282026273 |
| 13 | 392427087780 |
| 14 | 8146462590683 |
| 15 | 180629845193090 |
| 16 | 4261044215912232 |
| 17 | 106571080784076813 |
| 18 | 2817142524095598771 |
[1,1,2,7,38,279,2535,27106,330998,4526827, 68402684,1130591607,20282026273,392427087780, 8146462590683,180629845193090,4261044215912232, 106571080784076813,2817142524095598771] |