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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 8 |
| 4 | 34 |
| 5 | 91 |
| 6 | 386 |
| 7 | 1205 |
| 8 | 5146 |
| 9 | 17422 |
| 10 | 75144 |
| 11 | 267296 |
| 12 | 1161554 |
| 13 | 4276938 |
| 14 | 18677450 |
| 15 | 70571075 |
| 16 | 309208856 |
| 17 | 1191846297 |
| 18 | 5234648979 |
| 19 | 20497505744 |
| 20 | 90190143442 |
| 21 | 357689841471 |
| 22 | 1576087185005 |
| 23 | 6316705181733 |
| 24 | 27864624569679 |
| 25 | 112664602409092 |
| 26 | 497446084425379 |
| 27 | 2026418825472279 |
| 28 | 8953939800573176 |
[1,1,4,8,34,91,386,1205,5146,17422,75144,267296, 1161554,4276938,18677450,70571075,309208856, 1191846297,5234648979,20497505744,90190143442, 357689841471,1576087185005,6316705181733, 27864624569679,112664602409092,497446084425379, 2026418825472279,8953939800573176] |