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| n | a(n) |
|---|---|
| 1 | 20 |
| 2 | 44 |
| 3 | 92 |
| 4 | 178 |
| 5 | 348 |
| 6 | 658 |
| 7 | 1260 |
| 8 | 2382 |
| 9 | 4548 |
| 10 | 8658 |
| 11 | 16604 |
| 12 | 31894 |
| 13 | 61596 |
| 14 | 119362 |
| 15 | 232212 |
| 16 | 453438 |
| 17 | 887916 |
| 18 | 1744602 |
| 19 | 3434636 |
| 20 | 6780910 |
| 21 | 13405764 |
| 22 | 26561986 |
| 23 | 52679004 |
| 24 | 104653254 |
| 25 | 208038684 |
| 26 | 414084306 |
| 27 | 824553428 |
| 28 | 1643457646 |
| 29 | 3276588012 |
[20,44,92,178,348,658,1260,2382,4548,8658,16604, 31894,61596,119362,232212,453438,887916,1744602, 3434636,6780910,13405764,26561986,52679004, 104653254,208038684,414084306,824553428, 1643457646,3276588012] |