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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 15 |
| 3 | 53 |
| 4 | 146 |
| 5 | 356 |
| 6 | 809 |
| 7 | 1759 |
| 8 | 3716 |
| 9 | 7702 |
| 10 | 15763 |
| 11 | 31993 |
| 12 | 64582 |
| 13 | 129912 |
| 14 | 260749 |
| 15 | 522627 |
| 16 | 1046616 |
| 17 | 2094858 |
| 18 | 4191639 |
| 19 | 8385533 |
| 20 | 16773690 |
| 21 | 33550412 |
| 22 | 67104305 |
| 23 | 134212583 |
| 24 | 268429676 |
| 25 | 536864446 |
| 26 | 1073734619 |
| 27 | 2147475649 |
| 28 | 4294958446 |
| 29 | 8589924832 |
| 30 | 17179858453 |
[2,15,53,146,356,809,1759,3716,7702,15763,31993, 64582,129912,260749,522627,1046616,2094858, 4191639,8385533,16773690,33550412,67104305, 134212583,268429676,536864446,1073734619, 2147475649,4294958446,8589924832,17179858453] |