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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 72 |
| 3 | 576 |
| 4 | 4608 |
| 5 | 36864 |
| 6 | 294912 |
| 7 | 2359296 |
| 8 | 18874368 |
| 9 | 150994944 |
| 10 | 1207959552 |
| 11 | 9663676416 |
| 12 | 77309411328 |
| 13 | 618475290624 |
| 14 | 4947802324992 |
| 15 | 39582418599936 |
| 16 | 316659348799488 |
| 17 | 2533274790395904 |
| 18 | 20266198323167232 |
| 19 | 162129586585337856 |
[1,9,72,576,4608,36864,294912,2359296,18874368, 150994944,1207959552,9663676416,77309411328, 618475290624,4947802324992,39582418599936, 316659348799488,2533274790395904, 20266198323167232,162129586585337856] |