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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 3 |
| 5 | 9 |
| 6 | 29 |
| 7 | 57 |
| 8 | 135 |
| 9 | 615 |
| 10 | 2635 |
| 11 | 6273 |
| 12 | 25151 |
| 13 | 82623 |
| 14 | 525281 |
| 15 | 2941047 |
| 16 | 9100709 |
| 17 | 38766777 |
| 18 | 205155713 |
| 19 | 902705793 |
| 20 | 7714938567 |
| 21 | 52987356783 |
| 22 | 204844103977 |
| 23 | 1042657233471 |
| 24 | 5520661314689 |
| 25 | 38159472253821 |
| 26 | 211945677298567 |
| 27 | 2404720648663335 |
| 28 | 19773733727088813 |
[1,1,1,3,3,9,29,57,135,615,2635,6273,25151,82623, 525281,2941047,9100709,38766777,205155713, 902705793,7714938567,52987356783,204844103977, 1042657233471,5520661314689,38159472253821, 211945677298567,2404720648663335, 19773733727088813] |