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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 11 |
| 4 | 28 |
| 5 | 63 |
| 6 | 139 |
| 7 | 328 |
| 8 | 735 |
| 9 | 1684 |
| 10 | 3853 |
| 11 | 8750 |
| 12 | 20021 |
| 13 | 45627 |
| 14 | 104068 |
| 15 | 237541 |
| 16 | 541649 |
| 17 | 1235897 |
| 18 | 2819380 |
| 19 | 6431345 |
| 20 | 14672588 |
| 21 | 33470945 |
| 22 | 76356833 |
| 23 | 174191649 |
| 24 | 397374570 |
| 25 | 906523725 |
| 26 | 2068021039 |
| 27 | 4717711395 |
| 28 | 10762383681 |
| 29 | 24551876711 |
[2,6,11,28,63,139,328,735,1684,3853,8750,20021, 45627,104068,237541,541649,1235897,2819380, 6431345,14672588,33470945,76356833,174191649, 397374570,906523725,2068021039,4717711395, 10762383681,24551876711] |