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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 42 |
| 2 | 966 |
| 3 | 16100 |
| 4 | 217350 |
| 5 | 2521260 |
| 6 | 26053020 |
| 7 | 245642760 |
| 8 | 2149374150 |
| 9 | 17672631900 |
| 10 | 137846528820 |
| 11 | 1027583214840 |
| 12 | 7364346373020 |
| 13 | 50983936428600 |
| 14 | 342320716020600 |
| 15 | 2236495344667920 |
| 16 | 14257657822257990 |
| 17 | 88900689950549820 |
| 18 | 543281994142248900 |
| 19 | 3259691964853493400 |
[1,42,966,16100,217350,2521260,26053020,245642760, 2149374150,17672631900,137846528820,1027583214840, 7364346373020,50983936428600,342320716020600, 2236495344667920,14257657822257990, 88900689950549820,543281994142248900, 3259691964853493400] |