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| n | a(n) |
|---|---|
| 1 | 50 |
| 2 | 218 |
| 3 | 970 |
| 4 | 4194 |
| 5 | 18246 |
| 6 | 79778 |
| 7 | 347530 |
| 8 | 1514138 |
| 9 | 6603034 |
| 10 | 28783358 |
| 11 | 125459410 |
| 12 | 546925146 |
| 13 | 2384168474 |
| 14 | 10392867762 |
| 15 | 45304600806 |
| 16 | 197491613026 |
| 17 | 860900508458 |
| 18 | 3752824392746 |
| 19 | 16359260883466 |
| 20 | 71313013661214 |
| 21 | 310866547441298 |
[50,218,970,4194,18246,79778,347530,1514138, 6603034,28783358,125459410,546925146,2384168474, 10392867762,45304600806,197491613026,860900508458, 3752824392746,16359260883466,71313013661214, 310866547441298] |