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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 51 |
| 5 | 337 |
| 6 | 3500 |
| 7 | 60936 |
| 8 | 1866002 |
| 9 | 102768062 |
| 10 | 10296340496 |
| 11 | 1890236147880 |
| 12 | 639528747831552 |
| 13 | 400813006079742544 |
| 14 | 467517947968588109568 |
| 15 | 1019290779610824185400096 |
| 16 | 4170141472168738281510957264 |
| 17 | 32130367702064742239376997422512 |
[1,1,3,11,51,337,3500,60936,1866002,102768062, 10296340496,1890236147880,639528747831552, 400813006079742544,467517947968588109568, 1019290779610824185400096, 4170141472168738281510957264, 32130367702064742239376997422512] |