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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 24 |
| 4 | 285 |
| 5 | 4284 |
| 6 | 75978 |
| 7 | 1530720 |
| 8 | 34237485 |
| 9 | 837481140 |
| 10 | 22170740526 |
| 11 | 630399084912 |
| 12 | 19141524214722 |
| 13 | 617861322312696 |
| 14 | 21122842522288500 |
| 15 | 762448141026794880 |
| 16 | 28980030721635717885 |
| 17 | 1157145229347334181604 |
| 18 | 48434042350706316375942 |
| 19 | 2121007271655295076291280 |
| 20 | 97002622108401462159296310 |
[1,3,24,285,4284,75978,1530720,34237485,837481140, 22170740526,630399084912,19141524214722, 617861322312696,21122842522288500, 762448141026794880,28980030721635717885, 1157145229347334181604,48434042350706316375942, 2121007271655295076291280, 97002622108401462159296310] |