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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 14 |
| 5 | 25 |
| 6 | 41 |
| 7 | 74 |
| 8 | 124 |
| 9 | 222 |
| 10 | 390 |
| 11 | 706 |
| 12 | 1262 |
| 13 | 2324 |
| 14 | 4244 |
| 15 | 7869 |
| 16 | 14607 |
| 17 | 27337 |
| 18 | 51243 |
| 19 | 96665 |
| 20 | 182666 |
| 21 | 346647 |
| 22 | 659206 |
| 23 | 1257287 |
| 24 | 2402569 |
| 25 | 4601771 |
| 26 | 8828741 |
| 27 | 16969511 |
| 28 | 32665154 |
| 29 | 62972932 |
[2,4,8,14,25,41,74,124,222,390,706,1262,2324,4244, 7869,14607,27337,51243,96665,182666,346647,659206, 1257287,2402569,4601771,8828741,16969511,32665154, 62972932] |