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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 12 |
| 4 | 48 |
| 5 | 192 |
| 6 | 832 |
| 7 | 3712 |
| 8 | 17152 |
| 9 | 81152 |
| 10 | 392192 |
| 11 | 1928192 |
| 12 | 9621504 |
| 13 | 48623616 |
| 14 | 248463360 |
| 15 | 1282031616 |
| 16 | 6672285696 |
| 17 | 34993274880 |
| 18 | 184793432064 |
| 19 | 981947645952 |
| 20 | 5247335399424 |
| 21 | 28185150357504 |
| 22 | 152104870084608 |
| 23 | 824404913160192 |
| 24 | 4486067252101120 |
| 25 | 24501262150008832 |
| 26 | 134274187559698432 |
| 27 | 738200201575006208 |
[1,1,4,12,48,192,832,3712,17152,81152,392192, 1928192,9621504,48623616,248463360,1282031616, 6672285696,34993274880,184793432064,981947645952, 5247335399424,28185150357504,152104870084608, 824404913160192,4486067252101120, 24501262150008832,134274187559698432, 738200201575006208] |