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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 36 |
| 4 | 176 |
| 5 | 928 |
| 6 | 5296 |
| 7 | 33024 |
| 8 | 227776 |
| 9 | 1757504 |
| 10 | 15269888 |
| 11 | 149327616 |
| 12 | 1632715520 |
| 13 | 19758502912 |
| 14 | 261836047360 |
| 15 | 3763432774656 |
| 16 | 58208166178816 |
| 17 | 962637398577152 |
| 18 | 16934963591229440 |
| 19 | 315578267054112768 |
[1,2,8,36,176,928,5296,33024,227776,1757504, 15269888,149327616,1632715520,19758502912, 261836047360,3763432774656,58208166178816, 962637398577152,16934963591229440, 315578267054112768] |