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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 14 |
| 3 | 63 |
| 4 | 302 |
| 5 | 1440 |
| 6 | 7020 |
| 7 | 34175 |
| 8 | 167978 |
| 9 | 825688 |
| 10 | 4078284 |
| 11 | 20152606 |
| 12 | 99849580 |
| 13 | 494979560 |
| 14 | 2457666200 |
| 15 | 12208697151 |
| 16 | 60709727410 |
| 17 | 302015454120 |
| 18 | 1503479139724 |
| 19 | 7487167558122 |
| 20 | 37303246441268 |
| 21 | 185909155131480 |
| 22 | 926845403327304 |
| 23 | 4621854727637926 |
| 24 | 23053660002910820 |
| 25 | 115013127548121776 |
[1,3,14,63,302,1440,7020,34175,167978,825688, 4078284,20152606,99849580,494979560,2457666200, 12208697151,60709727410,302015454120, 1503479139724,7487167558122,37303246441268, 185909155131480,926845403327304,4621854727637926, 23053660002910820,115013127548121776] |