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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 11 |
| 5 | 48 |
| 6 | 236 |
| 7 | 1248 |
| 8 | 6896 |
| 9 | 39168 |
| 10 | 226496 |
| 11 | 1325568 |
| 12 | 7821056 |
| 13 | 46399488 |
| 14 | 276294656 |
| 15 | 1649369088 |
| 16 | 9862639616 |
| 17 | 59041579008 |
| 18 | 353712521216 |
| 19 | 2120127479808 |
| 20 | 12712174616576 |
| 21 | 76238687305728 |
| 22 | 457294683570176 |
| 23 | 2743218342985728 |
[1,1,3,11,48,236,1248,6896,39168,226496,1325568, 7821056,46399488,276294656,1649369088,9862639616, 59041579008,353712521216,2120127479808, 12712174616576,76238687305728,457294683570176, 2743218342985728] |