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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 36 |
| 4 | 114 |
| 5 | 558 |
| 6 | 1856 |
| 7 | 9384 |
| 8 | 31942 |
| 9 | 164322 |
| 10 | 566928 |
| 11 | 2948184 |
| 12 | 10262004 |
| 13 | 53761068 |
| 14 | 188306112 |
| 15 | 991821456 |
| 16 | 3490234182 |
| 17 | 18458523378 |
| 18 | 65190481904 |
| 19 | 345875613144 |
| 20 | 1225052975644 |
| 21 | 6516499594212 |
| 22 | 23134851823872 |
| 23 | 123325174525104 |
[1,3,8,36,114,558,1856,9384,31942,164322,566928, 2948184,10262004,53761068,188306112,991821456, 3490234182,18458523378,65190481904,345875613144, 1225052975644,6516499594212,23134851823872, 123325174525104] |