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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 24 |
| 6 | 80 |
| 7 | 456 |
| 8 | 2368 |
| 9 | 20352 |
| 10 | 139648 |
| 11 | 1577984 |
| 12 | 13327360 |
| 13 | 185992832 |
| 14 | 1860708096 |
| 15 | 30882985472 |
| 16 | 356724338688 |
| 17 | 6860887896064 |
| 18 | 89815091306496 |
| 19 | 1963843714723840 |
| 20 | 28724760194564096 |
| 21 | 703639672161697792 |
| 22 | 11370790299166343168 |
| 23 | 308435832182144040960 |
| 24 | 5456591088206554333184 |
| 25 | 162354575283061816197120 |
[0,1,2,4,8,24,80,456,2368,20352,139648,1577984, 13327360,185992832,1860708096,30882985472, 356724338688,6860887896064,89815091306496, 1963843714723840,28724760194564096, 703639672161697792,11370790299166343168, 308435832182144040960,5456591088206554333184, 162354575283061816197120] |