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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 19 |
| 5 | 48 |
| 6 | 131 |
| 7 | 348 |
| 8 | 954 |
| 9 | 2607 |
| 10 | 7212 |
| 11 | 19995 |
| 12 | 55816 |
| 13 | 156246 |
| 14 | 439267 |
| 15 | 1238397 |
| 16 | 3502004 |
| 17 | 9927260 |
| 18 | 28208628 |
| 19 | 80322048 |
| 20 | 229161413 |
| 21 | 654966245 |
| 22 | 1875074366 |
| 23 | 5376298225 |
| 24 | 15437286706 |
| 25 | 44385247519 |
| 26 | 127776425727 |
| 27 | 368276055467 |
| 28 | 1062618076382 |
| 29 | 3069264747076 |
[1,1,3,7,19,48,131,348,954,2607,7212,19995,55816, 156246,439267,1238397,3502004,9927260,28208628, 80322048,229161413,654966245,1875074366, 5376298225,15437286706,44385247519,127776425727, 368276055467,1062618076382,3069264747076] |