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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 14 |
| 4 | 59 |
| 5 | 257 |
| 6 | 1185 |
| 7 | 5609 |
| 8 | 27259 |
| 9 | 134911 |
| 10 | 678252 |
| 11 | 3452924 |
| 12 | 17767047 |
| 13 | 92248717 |
| 14 | 482710548 |
| 15 | 2543031236 |
| 16 | 13477141627 |
| 17 | 71800541745 |
| 18 | 384320284096 |
| 19 | 2065782153388 |
| 20 | 11146084675905 |
| 21 | 60346599617759 |
| 22 | 327749929622743 |
| 23 | 1785153353416807 |
| 24 | 9748766110978057 |
| 25 | 53367282644562541 |
[1,1,4,14,59,257,1185,5609,27259,134911,678252, 3452924,17767047,92248717,482710548,2543031236, 13477141627,71800541745,384320284096, 2065782153388,11146084675905,60346599617759, 327749929622743,1785153353416807,9748766110978057, 53367282644562541] |