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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 25 |
| 4 | 99 |
| 5 | 404 |
| 6 | 1710 |
| 7 | 7397 |
| 8 | 32598 |
| 9 | 145601 |
| 10 | 657960 |
| 11 | 3000643 |
| 12 | 13791325 |
| 13 | 63806466 |
| 14 | 296873158 |
| 15 | 1388007345 |
| 16 | 6517379983 |
| 17 | 30717477390 |
| 18 | 145259967469 |
| 19 | 688974178087 |
| 20 | 3276592282215 |
| 21 | 15620378854390 |
| 22 | 74630234665050 |
| 23 | 357278349533557 |
| 24 | 1713537162879366 |
| 25 | 8232110673000747 |
| 26 | 39609752128758538 |
| 27 | 190860289784929949 |
[1,2,7,25,99,404,1710,7397,32598,145601,657960, 3000643,13791325,63806466,296873158,1388007345, 6517379983,30717477390,145259967469,688974178087, 3276592282215,15620378854390,74630234665050, 357278349533557,1713537162879366,8232110673000747, 39609752128758538,190860289784929949] |