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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 40 |
| 3 | 185 |
| 4 | 816 |
| 5 | 3480 |
| 6 | 14444 |
| 7 | 58381 |
| 8 | 235277 |
| 9 | 944969 |
| 10 | 3788801 |
| 11 | 15172957 |
| 12 | 60719577 |
| 13 | 242889153 |
| 14 | 971616601 |
| 15 | 3886616229 |
[1,8,40,185,816,3480,14444,58381,235277,944969, 3788801,15172957,60719577,242889153,971616601, 3886616229] |