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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 18 |
| 3 | 90 |
| 4 | 672 |
| 5 | 7858 |
| 6 | 138956 |
| 7 | 3816148 |
| 8 | 159427052 |
| 9 | 10305467946 |
| 10 | 1016480307410 |
| 11 | 154783529107972 |
| 12 | 36032460970618398 |
| 13 | 12930394865167766832 |
| 14 | 7102572782942842968972 |
| 15 | 6007897214058607933844528 |
[6,18,90,672,7858,138956,3816148,159427052, 10305467946,1016480307410,154783529107972, 36032460970618398,12930394865167766832, 7102572782942842968972,6007897214058607933844528] |