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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 55 |
| 4 | 556 |
| 5 | 7839 |
| 6 | 118141 |
| 7 | 2488800 |
| 8 | 54871741 |
| 9 | 1374282325 |
| 10 | 35786212191 |
| 11 | 1182319284628 |
| 12 | 40234641889543 |
| 13 | 1409394785418633 |
| 14 | 53597236487797597 |
| 15 | 2091701617809524916 |
| 16 | 96271871655725943733 |
| 17 | 4719413412748380767833 |
| 18 | 240786355921823145103216 |
| 19 | 13247968989113021361444713 |
[1,6,55,556,7839,118141,2488800,54871741, 1374282325,35786212191,1182319284628, 40234641889543,1409394785418633,53597236487797597, 2091701617809524916,96271871655725943733, 4719413412748380767833,240786355921823145103216, 13247968989113021361444713] |