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| n | a(n) |
|---|---|
| -1 | 1 |
| 0 | 3 |
| 1 | 27 |
| 2 | 86 |
| 3 | 243 |
| 4 | 594 |
| 5 | 1370 |
| 6 | 2916 |
| 7 | 5967 |
| 8 | 11586 |
| 9 | 21870 |
| 10 | 39852 |
| 11 | 71052 |
| 12 | 123444 |
| 13 | 210654 |
| 14 | 352480 |
| 15 | 581013 |
| 16 | 942786 |
| 17 | 1510254 |
| 18 | 2388204 |
| 19 | 3734964 |
| 20 | 5777788 |
| 21 | 8852004 |
| 22 | 13434984 |
| 23 | 20218395 |
| 24 | 30177684 |
| 25 | 44704413 |
| 26 | 65743348 |
| 27 | 96033357 |
| 28 | 139368816 |
[1,3,27,86,243,594,1370,2916,5967,11586,21870, 39852,71052,123444,210654,352480,581013,942786, 1510254,2388204,3734964,5777788,8852004,13434984, 20218395,30177684,44704413,65743348,96033357, 139368816] |