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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 15 |
| 4 | 105 |
| 5 | 903 |
| 6 | 8778 |
| 7 | 92235 |
| 8 | 1023165 |
| 9 | 11821953 |
| 10 | 141061206 |
| 11 | 1727926291 |
| 12 | 21634600078 |
| 13 | 275950576450 |
| 14 | 3576315994020 |
| 15 | 46995014634435 |
| 16 | 625082431593285 |
| 17 | 8403885851894445 |
| 18 | 114069364107664350 |
| 19 | 1561609592248119645 |
| 20 | 21543838447412548410 |
| 21 | 299299110959202973710 |
[1,3,15,105,903,8778,92235,1023165,11821953, 141061206,1727926291,21634600078,275950576450, 3576315994020,46995014634435,625082431593285, 8403885851894445,114069364107664350, 1561609592248119645,21543838447412548410, 299299110959202973710] |