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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 15 |
| 3 | 33 |
| 4 | 87 |
| 5 | 238 |
| 6 | 697 |
| 7 | 1942 |
| 8 | 5656 |
| 9 | 16487 |
| 10 | 48053 |
| 11 | 140187 |
| 12 | 410230 |
| 13 | 1200987 |
| 14 | 3516338 |
| 15 | 10303811 |
| 16 | 30218936 |
| 17 | 88682815 |
| 18 | 260386129 |
| 19 | 764851328 |
| 20 | 2247357212 |
| 21 | 6604868430 |
| 22 | 19414622795 |
| 23 | 57075791496 |
| 24 | 167812063057 |
| 25 | 493440845883 |
| 26 | 1451046727997 |
[2,15,33,87,238,697,1942,5656,16487,48053,140187, 410230,1200987,3516338,10303811,30218936,88682815, 260386129,764851328,2247357212,6604868430, 19414622795,57075791496,167812063057,493440845883, 1451046727997] |