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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 52 |
| 6 | 203 |
| 7 | 877 |
| 8 | 4140 |
| 9 | 21147 |
| 10 | 115975 |
| 11 | 678569 |
| 12 | 4213584 |
| 13 | 27644267 |
| 14 | 190897305 |
| 15 | 1382935569 |
| 16 | 10479884654 |
| 17 | 82861996310 |
| 18 | 682044632178 |
| 19 | 5832378929502 |
| 20 | 51720008131148 |
| 21 | 474821737584174 |
| 22 | 4506150050048604 |
| 23 | 44145239041717738 |
| 24 | 445876518513670356 |
[1,1,2,5,15,52,203,877,4140,21147,115975,678569, 4213584,27644267,190897305,1382935569,10479884654, 82861996310,682044632178,5832378929502, 51720008131148,474821737584174,4506150050048604, 44145239041717738,445876518513670356] |