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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 33 |
| 3 | 991 |
| 4 | 63060 |
| 5 | 7018860 |
| 6 | 1206748720 |
| 7 | 295775068680 |
| 8 | 97835325011235 |
| 9 | 41970842737399345 |
| 10 | 22655642596496388759 |
| 11 | 15025240474194493147857 |
| 12 | 12008582230377080862401692 |
| 13 | 11382727559611560650861409564 |
| 14 | 12625404970864692720119281536900 |
| 15 | 16199644066580777034289339157904220 |
[1,3,33,991,63060,7018860,1206748720,295775068680, 97835325011235,41970842737399345, 22655642596496388759,15025240474194493147857, 12008582230377080862401692, 11382727559611560650861409564, 12625404970864692720119281536900, 16199644066580777034289339157904220] |