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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 31 |
| 5 | 119 |
| 6 | 456 |
| 7 | 1749 |
| 8 | 6721 |
| 9 | 25883 |
| 10 | 99892 |
| 11 | 386308 |
| 12 | 1496782 |
| 13 | 5809478 |
| 14 | 22584160 |
| 15 | 87922215 |
| 16 | 342741285 |
| 17 | 1337698515 |
| 18 | 5226732060 |
| 19 | 20442936360 |
| 20 | 80031775890 |
| 21 | 313585934610 |
| 22 | 1229695855440 |
| 23 | 4825705232010 |
| 24 | 18950613058026 |
| 25 | 74467158658974 |
| 26 | 292797216620776 |
| 27 | 1151895428382104 |
[0,1,2,8,31,119,456,1749,6721,25883,99892,386308, 1496782,5809478,22584160,87922215,342741285, 1337698515,5226732060,20442936360,80031775890, 313585934610,1229695855440,4825705232010, 18950613058026,74467158658974,292797216620776, 1151895428382104] |