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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 7 |
| 3 | 15 |
| 4 | 37 |
| 5 | 93 |
| 6 | 239 |
| 7 | 619 |
| 8 | 1611 |
| 9 | 4203 |
| 10 | 10981 |
| 11 | 28713 |
| 12 | 75115 |
| 13 | 196563 |
| 14 | 514463 |
| 15 | 1346647 |
| 16 | 3525189 |
| 17 | 9228453 |
| 18 | 24159415 |
| 19 | 63248571 |
| 20 | 165584323 |
| 21 | 433501203 |
| 22 | 1134914117 |
| 23 | 2971232785 |
| 24 | 7778770707 |
| 25 | 20365057443 |
| 26 | 53316366199 |
| 27 | 139583983839 |
| 28 | 365435492581 |
[3,7,15,37,93,239,619,1611,4203,10981,28713,75115, 196563,514463,1346647,3525189,9228453,24159415, 63248571,165584323,433501203,1134914117, 2971232785,7778770707,20365057443,53316366199, 139583983839,365435492581] |