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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 50 |
| 4 | 764 |
| 5 | 15804 |
| 6 | 413426 |
| 7 | 13094864 |
| 8 | 487323000 |
| 9 | 20844584760 |
| 10 | 1007739144312 |
| 11 | 54343954158240 |
| 12 | 3234285062655984 |
| 13 | 210581685526690464 |
| 14 | 14889759832273000320 |
| 15 | 1136236597054802033664 |
| 16 | 93074880409847175490560 |
| 17 | 8146156595011083708521472 |
[1,1,5,50,764,15804,413426,13094864,487323000, 20844584760,1007739144312,54343954158240, 3234285062655984,210581685526690464, 14889759832273000320,1136236597054802033664, 93074880409847175490560,8146156595011083708521472] |