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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 28 |
| 6 | 83 |
| 7 | 254 |
| 8 | 827 |
| 9 | 2724 |
| 10 | 9487 |
| 11 | 33462 |
| 12 | 121479 |
| 13 | 449168 |
| 14 | 1692977 |
| 15 | 6472741 |
| 16 | 25141274 |
| 17 | 98782902 |
| 18 | 392894212 |
| 19 | 1578743442 |
| 20 | 6404897025 |
| 21 | 26212710057 |
| 22 | 108149946290 |
| 23 | 449505848867 |
| 24 | 1881316282718 |
| 25 | 7923914364778 |
| 26 | 33574277467890 |
| 27 | 143047863493073 |
| 28 | 612639929663892 |
| 29 | 2636588347205559 |
[1,1,2,4,11,28,83,254,827,2724,9487,33462,121479, 449168,1692977,6472741,25141274,98782902, 392894212,1578743442,6404897025,26212710057, 108149946290,449505848867,1881316282718, 7923914364778,33574277467890,143047863493073, 612639929663892,2636588347205559] |