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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 31 |
| 5 | 110 |
| 6 | 413 |
| 7 | 1586 |
| 8 | 6338 |
| 9 | 25587 |
| 10 | 105668 |
| 11 | 441742 |
| 12 | 1869009 |
| 13 | 7988512 |
| 14 | 34452295 |
| 15 | 149655845 |
| 16 | 654683791 |
| 17 | 2880468569 |
| 18 | 12740749488 |
| 19 | 56624461023 |
| 20 | 252720799653 |
| 21 | 1132300360975 |
| 22 | 5091068882597 |
| 23 | 22963600275420 |
| 24 | 103884299000600 |
| 25 | 471227976010791 |
| 26 | 2142846539057306 |
| 27 | 9766818079951710 |
| 28 | 44610952963232566 |
[1,1,3,9,31,110,413,1586,6338,25587,105668,441742, 1869009,7988512,34452295,149655845,654683791, 2880468569,12740749488,56624461023,252720799653, 1132300360975,5091068882597,22963600275420, 103884299000600,471227976010791,2142846539057306, 9766818079951710,44610952963232566] |