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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 20 |
| 5 | 55 |
| 6 | 184 |
| 7 | 591 |
| 8 | 2022 |
| 9 | 7046 |
| 10 | 24888 |
| 11 | 90207 |
| 12 | 328888 |
| 13 | 1221276 |
| 14 | 4569389 |
| 15 | 17273315 |
| 16 | 65853981 |
| 17 | 252762675 |
| 18 | 977445345 |
| 19 | 3800281869 |
| 20 | 14860432632 |
| 21 | 58393802535 |
| 22 | 230495750196 |
| 23 | 913747733984 |
| 24 | 3635844012953 |
| 25 | 14520010283040 |
| 26 | 58176362311273 |
| 27 | 233814078106841 |
| 28 | 942421272344815 |
| 29 | 3808670709979013 |
[1,1,3,6,20,55,184,591,2022,7046,24888,90207, 328888,1221276,4569389,17273315,65853981, 252762675,977445345,3800281869,14860432632, 58393802535,230495750196,913747733984, 3635844012953,14520010283040,58176362311273, 233814078106841,942421272344815,3808670709979013] |