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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 17 |
| 5 | 43 |
| 6 | 110 |
| 7 | 286 |
| 8 | 753 |
| 9 | 2003 |
| 10 | 5376 |
| 11 | 14540 |
| 12 | 39589 |
| 13 | 108427 |
| 14 | 298512 |
| 15 | 825664 |
| 16 | 2293271 |
| 17 | 6393539 |
| 18 | 17885835 |
| 19 | 50191175 |
| 20 | 141247519 |
| 21 | 398537101 |
| 22 | 1127203038 |
| 23 | 3195229662 |
| 24 | 9076078057 |
| 25 | 25830193513 |
| 26 | 73643406563 |
| 27 | 210312889095 |
[1,1,3,7,17,43,110,286,753,2003,5376,14540,39589, 108427,298512,825664,2293271,6393539,17885835, 50191175,141247519,398537101,1127203038, 3195229662,9076078057,25830193513,73643406563, 210312889095] |