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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 25 |
| 4 | 154 |
| 5 | 882 |
| 6 | 5676 |
| 7 | 36465 |
| 8 | 244530 |
| 9 | 1657942 |
| 10 | 11471668 |
| 11 | 80242890 |
| 12 | 568080772 |
| 13 | 4056976900 |
| 14 | 29212908120 |
| 15 | 211783889025 |
| 16 | 1544811959970 |
| 17 | 11328491394990 |
| 18 | 83473572128100 |
| 19 | 617702666484750 |
| 20 | 4588654943721420 |
| 21 | 34206312386929020 |
| 22 | 255803818897858920 |
| 23 | 1918528298674328250 |
| 24 | 14427334095935095764 |
[1,1,6,25,154,882,5676,36465,244530,1657942, 11471668,80242890,568080772,4056976900, 29212908120,211783889025,1544811959970, 11328491394990,83473572128100,617702666484750, 4588654943721420,34206312386929020, 255803818897858920,1918528298674328250, 14427334095935095764] |