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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 22 |
| 5 | 87 |
| 6 | 355 |
| 7 | 1479 |
| 8 | 6278 |
| 9 | 27110 |
| 10 | 118841 |
| 11 | 527628 |
| 12 | 2367675 |
| 13 | 10720894 |
| 14 | 48920913 |
| 15 | 224735918 |
| 16 | 1038509478 |
| 17 | 4824103194 |
| 18 | 22513668516 |
| 19 | 105509641572 |
| 20 | 496337349317 |
| 21 | 2342869235037 |
| 22 | 11093615574663 |
| 23 | 52678904425461 |
| 24 | 250805844200643 |
| 25 | 1196978991435027 |
| 26 | 5725377773004857 |
[1,1,2,6,22,87,355,1479,6278,27110,118841,527628, 2367675,10720894,48920913,224735918,1038509478, 4824103194,22513668516,105509641572,496337349317, 2342869235037,11093615574663,52678904425461, 250805844200643,1196978991435027,5725377773004857] |