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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 15 |
| 5 | 31 |
| 6 | 72 |
| 7 | 155 |
| 8 | 340 |
| 9 | 738 |
| 10 | 1595 |
| 11 | 3424 |
| 12 | 7335 |
| 13 | 15642 |
| 14 | 33243 |
| 15 | 70432 |
| 16 | 148808 |
| 17 | 313571 |
| 18 | 659188 |
| 19 | 1382682 |
| 20 | 2894369 |
| 21 | 6047397 |
| 22 | 12613209 |
| 23 | 26265098 |
| 24 | 54610722 |
| 25 | 113387831 |
| 26 | 235117449 |
| 27 | 486933645 |
| 28 | 1007290340 |
| 29 | 2081469759 |
| 30 | 4296789924 |
| 31 | 8861401891 |
| 32 | 18258651137 |
| 33 | 37589337434 |
[1,3,6,15,31,72,155,340,738,1595,3424,7335,15642, 33243,70432,148808,313571,659188,1382682,2894369, 6047397,12613209,26265098,54610722,113387831, 235117449,486933645,1007290340,2081469759, 4296789924,8861401891,18258651137,37589337434] |