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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 30 |
| 5 | 102 |
| 6 | 397 |
| 7 | 1490 |
| 8 | 5979 |
| 9 | 24287 |
| 10 | 100419 |
| 11 | 422102 |
| 12 | 1801426 |
| 13 | 7746419 |
| 14 | 33739171 |
| 15 | 147966234 |
| 16 | 654198310 |
| 17 | 2911588244 |
| 18 | 13035624845 |
| 19 | 58685408132 |
| 20 | 265476086946 |
| 21 | 1206287649767 |
| 22 | 5504182850662 |
| 23 | 25206318950786 |
| 24 | 115837181027184 |
| 25 | 534037927543324 |
| 26 | 2469248650622062 |
| 27 | 11448682897131052 |
| 28 | 53217754670807911 |
[1,1,3,9,30,102,397,1490,5979,24287,100419,422102, 1801426,7746419,33739171,147966234,654198310, 2911588244,13035624845,58685408132,265476086946, 1206287649767,5504182850662,25206318950786, 115837181027184,534037927543324,2469248650622062, 11448682897131052,53217754670807911] |