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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 67 |
| 5 | 276 |
| 6 | 1212 |
| 7 | 5391 |
| 8 | 24003 |
| 9 | 107719 |
| 10 | 486728 |
| 11 | 2208735 |
| 12 | 10059868 |
| 13 | 45970367 |
| 14 | 210657177 |
| 15 | 967636566 |
| 16 | 4454109123 |
| 17 | 20540731356 |
| 18 | 94882599285 |
| 19 | 438931979661 |
| 20 | 2033217678792 |
| 21 | 9429562243530 |
| 22 | 43779688919145 |
| 23 | 203463271733010 |
| 24 | 946445226206940 |
| 25 | 4406251540834026 |
[1,1,3,16,67,276,1212,5391,24003,107719,486728, 2208735,10059868,45970367,210657177,967636566, 4454109123,20540731356,94882599285,438931979661, 2033217678792,9429562243530,43779688919145, 203463271733010,946445226206940,4406251540834026] |