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| n | a(n) |
|---|---|
| 1 | 63 |
| 2 | 234 |
| 3 | 864 |
| 4 | 3159 |
| 5 | 12879 |
| 6 | 51759 |
| 7 | 203391 |
| 8 | 898857 |
| 9 | 3877551 |
| 10 | 16120377 |
| 11 | 75287475 |
| 12 | 340653681 |
| 13 | 1468371483 |
| 14 | 7083577089 |
| 15 | 32959439379 |
| 16 | 145024403049 |
| 17 | 711949718619 |
| 18 | 3363197265009 |
| 19 | 14961791864691 |
| 20 | 74118576012057 |
| 21 | 352900936009611 |
[63,234,864,3159,12879,51759,203391,898857, 3877551,16120377,75287475,340653681,1468371483, 7083577089,32959439379,145024403049,711949718619, 3363197265009,14961791864691,74118576012057, 352900936009611] |