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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 80 |
| 3 | 860 |
| 4 | 6576 |
| 5 | 42112 |
| 6 | 242688 |
| 7 | 1306944 |
| 8 | 6721280 |
| 9 | 33448448 |
| 10 | 162435072 |
| 11 | 774052864 |
| 12 | 3633229824 |
| 13 | 16842670080 |
| 14 | 77264322560 |
| 15 | 351273107456 |
| 16 | 1584582819840 |
| 17 | 7098965819392 |
| 18 | 31609517506560 |
| 19 | 139978221551616 |
| 20 | 616818283642880 |
| 21 | 2705880365662208 |
| 22 | 11821908555202560 |
| 23 | 51457052429516800 |
[3,80,860,6576,42112,242688,1306944,6721280, 33448448,162435072,774052864,3633229824, 16842670080,77264322560,351273107456, 1584582819840,7098965819392,31609517506560, 139978221551616,616818283642880,2705880365662208, 11821908555202560,51457052429516800] |