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| n | a(n) |
|---|---|
| 4 | 1 |
| 5 | 2 |
| 6 | 7 |
| 7 | 22 |
| 8 | 68 |
| 9 | 214 |
| 10 | 691 |
| 11 | 2240 |
| 12 | 7396 |
| 13 | 24702 |
| 14 | 83469 |
| 15 | 284928 |
| 16 | 981814 |
| 17 | 3410990 |
| 18 | 11939752 |
| 19 | 42075308 |
| 20 | 149180356 |
| 21 | 531866972 |
| 22 | 1905872189 |
| 23 | 6861162880 |
| 24 | 24805796984 |
| 25 | 90035940942 |
| 26 | 327988261992 |
| 27 | 1198853954688 |
| 28 | 4395798528850 |
[1,2,7,22,68,214,691,2240,7396,24702,83469,284928, 981814,3410990,11939752,42075308,149180356, 531866972,1905872189,6861162880,24805796984, 90035940942,327988261992,1198853954688, 4395798528850] |