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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 16 |
| 5 | 33 |
| 6 | 71 |
| 7 | 141 |
| 8 | 284 |
| 9 | 552 |
| 10 | 1067 |
| 11 | 2020 |
| 12 | 3803 |
| 13 | 7043 |
| 14 | 12957 |
| 15 | 23566 |
| 16 | 42536 |
| 17 | 76068 |
| 18 | 135093 |
| 19 | 238001 |
| 20 | 416591 |
[1,3,7,16,33,71,141,284,552,1067,2020,3803,7043, 12957,23566,42536,76068,135093,238001,416591] |