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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 15 |
| 4 | 46 |
| 5 | 156 |
| 6 | 507 |
| 7 | 1637 |
| 8 | 5338 |
| 9 | 17401 |
| 10 | 56648 |
| 11 | 184384 |
| 12 | 600287 |
| 13 | 1954546 |
| 14 | 6363740 |
| 15 | 20718710 |
| 16 | 67455328 |
| 17 | 219621081 |
| 18 | 715042212 |
| 19 | 2328028685 |
| 20 | 7579574414 |
| 21 | 24677521267 |
| 22 | 80344901649 |
| 23 | 261586345777 |
| 24 | 851670870944 |
| 25 | 2772863697333 |
| 26 | 9027869180467 |
[1,5,15,46,156,507,1637,5338,17401,56648,184384, 600287,1954546,6363740,20718710,67455328, 219621081,715042212,2328028685,7579574414, 24677521267,80344901649,261586345777,851670870944, 2772863697333,9027869180467] |