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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 16 |
| 5 | 32 |
| 6 | 62 |
| 7 | 116 |
| 8 | 206 |
| 9 | 350 |
| 10 | 566 |
| 11 | 886 |
| 12 | 1334 |
| 13 | 1974 |
| 14 | 2846 |
| 15 | 3978 |
| 16 | 5472 |
| 17 | 7398 |
| 18 | 9854 |
| 19 | 12964 |
| 20 | 16804 |
| 21 | 21524 |
[2,4,8,16,32,62,116,206,350,566,886,1334,1974, 2846,3978,5472,7398,9854,12964,16804,21524] |