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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 5 |
| 5 | 13 |
| 6 | 32 |
| 7 | 94 |
| 8 | 297 |
| 9 | 1036 |
| 10 | 3911 |
| 11 | 15918 |
| 12 | 69350 |
| 13 | 321779 |
| 14 | 1582745 |
| 15 | 8220349 |
| 16 | 44925187 |
| 17 | 257563819 |
| 18 | 1544896976 |
| 19 | 9671289892 |
| 20 | 63051738167 |
| 21 | 427254561854 |
| 22 | 3003872526303 |
| 23 | 21876513464296 |
| 24 | 164790822258172 |
| 25 | 1282198404741305 |
| 26 | 10292007232817249 |
| 27 | 85126350266370355 |
[0,1,1,3,5,13,32,94,297,1036,3911,15918,69350, 321779,1582745,8220349,44925187,257563819, 1544896976,9671289892,63051738167,427254561854, 3003872526303,21876513464296,164790822258172, 1282198404741305,10292007232817249, 85126350266370355] |