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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 41 |
| 3 | 217 |
| 4 | 953 |
| 5 | 3961 |
| 6 | 16121 |
| 7 | 65017 |
| 8 | 261113 |
| 9 | 1046521 |
| 10 | 4190201 |
| 11 | 16769017 |
| 12 | 67092473 |
| 13 | 268402681 |
| 14 | 1073676281 |
| 15 | 4294836217 |
[1,4,41,217,953,3961,16121,65017,261113,1046521, 4190201,16769017,67092473,268402681,1073676281, 4294836217] |