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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 80 |
| 5 | 875 |
| 6 | 10584 |
| 7 | 170471 |
| 8 | 2949120 |
| 9 | 63772920 |
| 10 | 1441000000 |
| 11 | 38818444632 |
| 12 | 1089573617664 |
| 13 | 35185728919614 |
| 14 | 1175820172477440 |
| 15 | 44425722744140625 |
| 16 | 1722925924631969792 |
| 17 | 74364737115532234518 |
| 18 | 3291298649632850485248 |
| 19 | 159785357022861166517580 |
| 20 | 7932051456000000000000000 |
[1,1,2,12,80,875,10584,170471,2949120,63772920, 1441000000,38818444632,1089573617664, 35185728919614,1175820172477440,44425722744140625, 1722925924631969792,74364737115532234518, 3291298649632850485248,159785357022861166517580, 7932051456000000000000000] |