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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 72 |
| 4 | 18 |
| 5 | 342 |
| 6 | 927 |
| 7 | 7812 |
| 8 | 1656 |
| 9 | 38691 |
| 10 | 94095 |
| 11 | 741771 |
| 12 | 144135 |
| 13 | 3234951 |
| 14 | 9692874 |
| 15 | 70984341 |
| 16 | 12764034 |
| 17 | 361041921 |
| 18 | 984024783 |
| 19 | 7641622611 |
| 20 | 1044876843 |
| 21 | 30235306401 |
| 22 | 90695018313 |
| 23 | 72887134149 |
| 24 | 184635924282 |
| 25 | 344906882748 |
| 26 | 9238285681452 |
| 27 | 7894847955267 |
[1,3,9,72,18,342,927,7812,1656,38691,94095,741771, 144135,3234951,9692874,70984341,12764034, 361041921,984024783,7641622611,1044876843, 30235306401,90695018313,72887134149,184635924282, 344906882748,9238285681452,7894847955267] |