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| n | a(n) |
|---|---|
| 1 | 18 |
| 2 | 29 |
| 3 | 69 |
| 4 | 133 |
| 5 | 236 |
| 6 | 472 |
| 7 | 940 |
| 8 | 1781 |
| 9 | 3433 |
| 10 | 6725 |
| 11 | 13008 |
| 12 | 25088 |
| 13 | 48696 |
| 14 | 94445 |
| 15 | 182717 |
| 16 | 353893 |
| 17 | 685924 |
| 18 | 1328520 |
| 19 | 2572916 |
| 20 | 4984581 |
| 21 | 9656065 |
| 22 | 18703333 |
| 23 | 36229992 |
| 24 | 70182768 |
| 25 | 135948832 |
| 26 | 263342141 |
| 27 | 510120437 |
| 28 | 988149701 |
| 29 | 1914124956 |
| 30 | 3707828408 |
[18,29,69,133,236,472,940,1781,3433,6725,13008, 25088,48696,94445,182717,353893,685924,1328520, 2572916,4984581,9656065,18703333,36229992, 70182768,135948832,263342141,510120437,988149701, 1914124956,3707828408] |