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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 27 |
| 4 | 108 |
| 5 | 459 |
| 6 | 1994 |
| 7 | 8804 |
| 8 | 39668 |
| 9 | 180345 |
| 10 | 828261 |
| 11 | 3835665 |
| 12 | 17869380 |
| 13 | 83746921 |
| 14 | 394258798 |
| 15 | 1863940882 |
| 16 | 8844326213 |
| 17 | 42094388136 |
| 18 | 200934619614 |
| 19 | 961528165333 |
| 20 | 4611556549374 |
| 21 | 22163105762414 |
| 22 | 106712056107950 |
| 23 | 514676230609664 |
| 24 | 2486127145587815 |
| 25 | 12026281544464482 |
| 26 | 58251743422904915 |
| 27 | 282493832836296113 |
[1,2,7,27,108,459,1994,8804,39668,180345,828261, 3835665,17869380,83746921,394258798,1863940882, 8844326213,42094388136,200934619614,961528165333, 4611556549374,22163105762414,106712056107950, 514676230609664,2486127145587815, 12026281544464482,58251743422904915, 282493832836296113] |