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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 36 |
| 6 | 243 |
| 7 | 2016 |
| 8 | 19745 |
| 9 | 222318 |
| 10 | 2824546 |
| 11 | 39938124 |
| 12 | 621808679 |
| 13 | 10569132576 |
| 14 | 194745803641 |
| 15 | 3866820606006 |
| 16 | 82313887902511 |
| 17 | 1870203518285750 |
| 18 | 45174881008705328 |
| 19 | 1156071783429567906 |
| 20 | 31246398342838909318 |
[1,1,2,7,36,243,2016,19745,222318,2824546, 39938124,621808679,10569132576,194745803641, 3866820606006,82313887902511,1870203518285750, 45174881008705328,1156071783429567906, 31246398342838909318] |