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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 71 |
| 3 | 561 |
| 4 | 4433 |
| 5 | 35031 |
| 6 | 276827 |
| 7 | 2187585 |
| 8 | 17287073 |
| 9 | 136608591 |
| 10 | 1079529611 |
| 11 | 8530826457 |
| 12 | 67413620993 |
| 13 | 532726379847 |
| 14 | 4209793089371 |
| 15 | 33267280400913 |
| 16 | 262889866978817 |
| 17 | 2077449112980255 |
| 18 | 16416740845208075 |
| 19 | 129730917736941417 |
| 20 | 1025179795159015841 |
[1,9,71,561,4433,35031,276827,2187585,17287073, 136608591,1079529611,8530826457,67413620993, 532726379847,4209793089371,33267280400913, 262889866978817,2077449112980255, 16416740845208075,129730917736941417, 1025179795159015841] |