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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 20 |
| 5 | 49 |
| 6 | 172 |
| 7 | 484 |
| 8 | 1732 |
| 9 | 5194 |
| 10 | 19061 |
| 11 | 59840 |
| 12 | 222265 |
| 13 | 722995 |
| 14 | 2707778 |
| 15 | 9031024 |
| 16 | 34126550 |
| 17 | 116009638 |
| 18 | 440855651 |
| 19 | 1523827413 |
| 20 | 5816083375 |
| 21 | 20364473133 |
| 22 | 78075605101 |
| 23 | 276294402102 |
| 24 | 1062737326830 |
| 25 | 3796951739926 |
| 26 | 14643791215968 |
| 27 | 52733250282433 |
| 28 | 203923018220654 |
| 29 | 739335703065172 |
| 30 | 2865104006790009 |
[1,1,3,6,20,49,172,484,1732,5194,19061,59840, 222265,722995,2707778,9031024,34126550,116009638, 440855651,1523827413,5816083375,20364473133, 78075605101,276294402102,1062737326830, 3796951739926,14643791215968,52733250282433, 203923018220654,739335703065172,2865104006790009] |