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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 165 |
| 6 | 3465 |
| 7 | 148995 |
| 8 | 12664575 |
| 9 | 2165642325 |
| 10 | 738484032825 |
| 11 | 504384594419475 |
| 12 | 688484971382583375 |
| 13 | 1880252456845835197125 |
| 14 | 10268058666835106011499625 |
| 15 | 112158004817839862963610403875 |
[1,1,3,15,165,3465,148995,12664575,2165642325, 738484032825,504384594419475,688484971382583375, 1880252456845835197125,10268058666835106011499625, 112158004817839862963610403875] |