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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 105 |
| 5 | 933 |
| 6 | 9988 |
| 7 | 124449 |
| 8 | 1761287 |
| 9 | 27813479 |
| 10 | 483482018 |
| 11 | 9153385959 |
| 12 | 187129080977 |
| 13 | 4102129113670 |
| 14 | 95861136747795 |
| 15 | 2376234441556411 |
| 16 | 62216635372018209 |
| 17 | 1714347701138957189 |
| 18 | 49553280367466054768 |
| 19 | 1498300016807379304877 |
| 20 | 47270249397381096576643 |
[1,1,3,15,105,933,9988,124449,1761287,27813479, 483482018,9153385959,187129080977,4102129113670, 95861136747795,2376234441556411,62216635372018209, 1714347701138957189,49553280367466054768, 1498300016807379304877,47270249397381096576643] |