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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 24 |
| 5 | 169 |
| 6 | 2024 |
| 7 | 29584 |
| 8 | 525600 |
| 9 | 10764961 |
| 10 | 250030128 |
| 11 | 6484436676 |
| 12 | 185752964096 |
| 13 | 5824523694025 |
| 14 | 198428723433728 |
| 15 | 7298231591777344 |
| 16 | 288230377359679488 |
| 17 | 12165297972404595841 |
| 18 | 546477889989773968640 |
| 19 | 26031837574639154232100 |
| 20 | 1310720000002816000131072 |
[1,1,2,4,24,169,2024,29584,525600,10764961, 250030128,6484436676,185752964096,5824523694025, 198428723433728,7298231591777344, 288230377359679488,12165297972404595841, 546477889989773968640,26031837574639154232100, 1310720000002816000131072] |