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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 44 |
| 5 | 163 |
| 6 | 660 |
| 7 | 2744 |
| 8 | 11609 |
| 9 | 50491 |
| 10 | 222050 |
| 11 | 990487 |
| 12 | 4470299 |
| 13 | 20329678 |
| 14 | 93309453 |
| 15 | 430847108 |
| 16 | 2001760287 |
| 17 | 9349413398 |
| 18 | 43860569586 |
| 19 | 206640193818 |
| 20 | 977015030033 |
| 21 | 4634743021734 |
| 22 | 22052035654559 |
| 23 | 105201656349502 |
| 24 | 503122279367445 |
| 25 | 2411495205457281 |
| 26 | 11582161001516096 |
| 27 | 55732796605327564 |
[1,1,4,11,44,163,660,2744,11609,50491,222050, 990487,4470299,20329678,93309453,430847108, 2001760287,9349413398,43860569586,206640193818, 977015030033,4634743021734,22052035654559, 105201656349502,503122279367445,2411495205457281, 11582161001516096,55732796605327564] |