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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 22 |
| 6 | 57 |
| 7 | 156 |
| 8 | 447 |
| 9 | 1335 |
| 10 | 4140 |
| 11 | 13290 |
| 12 | 44055 |
| 13 | 150494 |
| 14 | 528860 |
| 15 | 1909010 |
| 16 | 7068879 |
| 17 | 26820161 |
| 18 | 104156616 |
| 19 | 413634176 |
| 20 | 1678323602 |
| 21 | 6952182325 |
| 22 | 29378908664 |
| 23 | 126568357635 |
| 24 | 555540596435 |
| 25 | 2482857618713 |
| 26 | 11292588202568 |
| 27 | 52241502972732 |
| 28 | 245700673227652 |
| 29 | 1174263543570678 |
| 30 | 5700387781450739 |
[1,1,2,4,9,22,57,156,447,1335,4140,13290,44055, 150494,528860,1909010,7068879,26820161,104156616, 413634176,1678323602,6952182325,29378908664, 126568357635,555540596435,2482857618713, 11292588202568,52241502972732,245700673227652, 1174263543570678,5700387781450739] |