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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 3 |
| 6 | 5 |
| 7 | 13 |
| 8 | 28 |
| 9 | 64 |
| 10 | 207 |
| 11 | 578 |
| 12 | 1685 |
| 13 | 6518 |
| 14 | 22361 |
| 15 | 79319 |
| 16 | 357180 |
| 17 | 1453177 |
| 18 | 6075215 |
| 19 | 31216968 |
| 20 | 146906126 |
| 21 | 707344776 |
| 22 | 4084254624 |
| 23 | 21823224623 |
| 24 | 118932148555 |
| 25 | 762346849634 |
| 26 | 4559139897594 |
| 27 | 27742486678915 |
| 28 | 195472113041924 |
[1,1,1,1,2,3,5,13,28,64,207,578,1685,6518,22361, 79319,357180,1453177,6075215,31216968,146906126, 707344776,4084254624,21823224623,118932148555, 762346849634,4559139897594,27742486678915, 195472113041924] |